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New Rotax SB - We all replace fuel pumps?

Bill_H

Well Known Member
On June 24, 2013 Rotax released a new SB on the old style fuel pumps. It is issued as "Recommended" rather than "Mandatory."
Before this one, all of the Rotax SBs about fuel pumps, fuel hoses, oil leaks, washer replacement, improperly torqued oil pump bolts, and possible crankshaft journal crack have been not applicable to my engine serial #.
Here is the SB (actually 2 of them issued the same day), I figured someone else would start this thread:

http://legacy.rotax-owner.com/si_tb_info/serviceb/sb-912-063.pdf
This is 14 pages
http://legacy.rotax-owner.com/si_tb_info/ServiceB/SB-912-063UL.pdf
This is 2 pages

The SB notes that "all fuel pumps have a 5 year life" in accordance with the Line Maintenance Manual. Thus fuel pumps prior to 2008 (with s/n starting 07. or 06.) should have already been replaced. It goes on to say that all fuel pumps with part # 892542 and 892546 (mine) are affected and also lists engine serial number ranges.
Fuel pump types 893110, 893114, 893115 are not affected.

The 14 page version has the details for replacing AND reusing the existing fuel lines and there is a video on that as well. Basically you cut the two old fuel lines at the pump then put them on the new pump with 4 of those Oetiker band clamps (2 for the rubber, 2 bigger ones for the firesleeve.) Of course you have the 5-year Rotax Rubber Replacement Recommendation to deal with...

The new pumps have longer connectors on them that make up for the cut-off length of the existing fuel line.

I have not inquired about price. My old-style fuel pump has less than 60 hours and has shown no leaks. I imagine there might be a "run" on them. Since it is "recommended" rather than "mandatory" I imagine there is no under-warranty price break. Anyone know? What are y'all doing?

Let's hear from our friends at Lockwood!

Bill H.
N412BR "Sweetie" Flying, just finished 1st Annual Inspection!
 
You covered it very well , Bill. I was a bit surprised when I discovered that the changes finally caught up with our style of pumps (ie 892546). It seems to me there was an earlier iteration that exempted that series pump. The ugly part of the replacement to me is removal of carb bowls which don't appear to be a fun thing. The big question is what to do, why, and by when? Before I rec'd the Rotaxowner notice yesterday my pump was fine, I thought. Now not so sure. I will see what Lockwood says as they are a good Rotax source of knowledge. I suspect maybe it will range from do it now to wait till it's five yrs old. Likely it will be next annual insp. We'll see.
Dick Seiders 120093
 
There is no need to do anything to the carbs to install the new fuel pump. See the video. You just (basically) cut the fuel pump ends of the existing lines and connect them to the newly installed fuel pump. The other end is unchanged.
 
Hey Bill, I believe the video says to check the bowls for potential contamination from the cutting of fuel lines. (twice).
Dick Seiders
 
Looks to me like if you cut carefully and rinse (maybe with a hypo) you wont get any contamination. Also rinse out the new fuel pump. I think you may cause more problems than you solve by messing with the other end of the carbs... (I'm a MikeBusch-ian"). I will re-watch because I don't remember them actually showing doing that step...
Perhaps there is some confusion with the Rotax SB having to do with some improper fuel lines they supplied that were breaking up and causing contamination.
 
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It's not that hard to check the carb bowels and I sure recommend it after cutting fuel hoses. Many of the Flight Design CT's turned 5 about a year ago and there were numerous problems related to particles in the fuel system after the mandated 5 yr hose change. Problems were related to hose brand but also carb hoses vs. FI hoses. But, the main problem appeared to be how carefully the hose was cut.

As for the SB, isn't it advisory? That, and being ELSA, there is no need to do anything. Right?? What am I missing? Having said that, I would be replacing my pump if I had a flying -12. To me, it's not worth ignoring the SB for a couple hundred bucks. On my CT it gets replaced for sure since I'm up against the 5 years

As for price, CPS is working up a price including the various pieces and clamps. I expect Kevin to post a price any day now on the CT forum.
 
I changed the pump early on - read ZERO HRS - because I didn't like the idea of raw fuel in the cowling from the old weep hole.

Rotax has a five year "all rubber" replacement requirement that will set you back about $1000 USD. Now, they've upped the ante to five years on the fuel pumps.

Since I ride around with my fat keester tied to the reliability of the Rotax huffing and puffing reliably in front of me, I'm reluctant to bad-mouth my power partner. But -- I will say they seem to be run by marketeers who would like you to replace the entire engine every five years to pump the P&L bottom line (even if it only has 200 hours), and Austrian lawyers (I thought we only had those parasites in the USA?) - while bragging about their 2000 hour TBO (about 10-15 change-outs of everything on the engine.....).

As I recall, these are the same guys who spec'd (and shipped) fuel lines whose interior linings were incompatible with gasoline.

Pardon me for being a "non-believer." Actually - I AM a believer - in Mike Bush and his minimalist approach. Messing with things causes more messes than not messing with them. The airlines learned this decades ago and went to "On-Condition" maintenance eons ago.

Meanwhile - I have a Zero Time old pump that I'm willing to part with at a reasonable price. The replacement - on a New, ZERO-Time engine -- cost me about $175 - if I remember correctly, and I have nothing to show for it except a line item on my Visa card bill.

Bob Bogash
N737G
 
I plan on using NAPA hoses when my hoses need replacement. May sound like heresy, but cars run just fine on them. I bought a replacement fuel pump a few months ago, but I haven't decided when I will swap out my old "AC" pump.
 
I asked Phil Lockwood the question about replacing the pump if there were no signs of issues with it before this SB came out. He pointed me to one of his senior techs who said it wasn't worth doing. He said they have several planes make it to TBO of the engine in flight schools without replacement. I have one on my Gobosh and am trying to decide what to do with the SB as well.

Carl
 
John, Sorry I am not familiar with a CT. I can assure you pulling the carb. bowls on a 12 is no small task primarily due to a lack of access space. Can be done of course but it's one of those jobs where you have to disturb a number of components which sometimes wind up creating new problems in addition to that which you are trying to address.
Personally the more I think about this SB the less inclined I am to do anything in view of fact the little bugger is performing very nicely. After all the SB content doesn't really tell us to do anything other than change the pump out after five years, or if not there yet no later than May 2014, but rather at the next maintanence event which I presume is the next Condition Inspection. At any rate barring a more convincing bit of news that is my plan.
Dick Seiders 120093
 
Dick- I haven't gotten to the point in my build where I am familiar with the -12 carb configuration.

On the CT, you have to remove the carb from the socket so you can lift it high enough above the drip trays to get at the bowl. Fortunately you can do this without removing fuel lines or linkages so no need to set up the carbs and balance them.

I was hoping the -12 would be easier, or at least no more difficult, than the CT. Sounds like that may not be the case.
 
Regarding the SB, there is an interesting personality type common amongst some engineers, lawyers, bureaucrats, legislators, certain European countries in particular, and companies that manufacture aircraft engines in Europe. It is the type that believes that "Everything must be either Mandatory or Forbidden." The fact that this "Recommended" (i.e. "Use your own judgement [?!!]") SB comes from such a mindset is quite telling and likely has a legalistic origin... Whatcha wanna bet it becomes mandatory? Or that the FAA turns it into an AD like the one they did on the bad fuel hoses?

Bill H. BSME La. Tech, '75 but quite iconoclastic for an engineer...
 
Checking carb bowls...

Now I am not one who would recommend pulling off the carb bowls on a sweetly running Rotax just because...but I have done it a couple times now and it is not difficult or scary. Remove the air cleaner, loosen the clamp holding the carb to the rubber socket and work the carb out of the socket. With all the linkages and hoses in place you can move it up enough to rotate the wire retainer aft and remove the bowl.
i-HKBZpKL-M.jpg

I had the oil tank off for the SB during my annual, but you don't need to have it off to get the carb bowl off. With the carb up like this you can also put your ball head allen wrench on the top right engine mount screw. I used Nord-lok washers on these so I check torque on them at annual. The screws haven't moved since the "troubles" a couple years ago. You also can check the rubber carb socket for any hardening or cracking. Mine are still fresh looking after 200 hours.

I have found that the gascolator screen does a good job of protecting the carbs, as you can see in this picture there is no debris in the fuel in the bowl. I use 92UL auto gas from high volume stations exclusively, with an occasional top up with 100LL when away from home.
i-BFbNPsH-M.jpg

It would probably be a good idea to have a spare bowl gasket on hand in case you damage one.

I put the carb balancer on after moving the carbs and found no change in the balance after moving the carbs.
So anyway, if you feel the need to look in the bowls, there is not much to fear.........although, my engine was running sooooo sweet and now after moving the carbs, do I detect a bit of roughness?
 
Now I am not one who would recommend pulling off the carb bowls on a sweetly running Rotax just because...
So anyway, if you feel the need to look in the bowls, there is not much to fear.........although, my engine was running sooooo sweet and now after moving the carbs, do I detect a bit of roughness?

Oh - Antonio - how could you? lawyers can't rule yer aeronautical life, or yer done for from the get-go..

If she's running sweetly, 'jes leave her that way.

Are you trying to please a bunch of Viennese lawyers sipping their Cappuccinos in some sidewalk cafe in Vienna???

Bob Bogash
N737G
 
It's not that hard to check the carb bowels and I sure recommend it after cutting fuel hoses. Many of the Flight Design CT's turned 5 about a year ago and there were numerous problems related to particles in the fuel system after the mandated 5 yr hose change. Problems were related to hose brand but also carb hoses vs. FI hoses. But, the main problem appeared to be how carefully the hose was cut.
We did OK after the 5-yr hose change on our CT. May have been our A&P, who worked on nothing but CTs.

We cleaned the carb bowls every annual. Too much junk accumulates in there and it was a simple task.

TODR
 
Tony, thanks for the great pics, but I suspect it does help on the rt side to have the oil tank off to get at the carb. The roughness you hear, feel, or imagine, would likely not be there if carbs were not moved around, but even if it's imagined thanks for making my point about messing with equpment that is running just fine.
Dick Seiders 120093
 
For those of you that might be wondering---yes you can use stainless braid teflon with crimped hose ends for your Rotax applications. I have several out there right now. For those using an ethanol fuel and a rubber hose, yep the 5 year replacement or sooner is advised. (If I can figure out how to post the pics, I will.)
Tom
 
Tom asked me to post this picture.

As he mentioned, we are able to build Stainless Braid Conductive teflon hoses and adapt them to a rotax/jabiru, etc. engine. We can effectively eliminate the 5 year replacement issue by using a hose that has no time rated life. In addition, we are able to provide a much more compact package that is lighter than the standard rubber hoses at an incredible price point.

There are some additional pictures and more information at:
http://www.aircraftspecialty.com/kitplanehoses/hoses.html

click on the "Rotax" tab.

Or, please email Tom at [email protected].

John%20Jones%20RV12%203.JPG
 
Thanks Bill, Bob, Tony and Dick,
This is a good conversation to have. I'm nearing completion of my RV12 and it's equipped with the pump that the SB says to replace. I have a question and the answer may be obvious, but I'm going to ask it anyway. If one were not to install the new pump, and the old pump failed would the electric pump carry the load so I could get to the ground without falling?
Scott
 
Complete 'retro' kit?

I'm about 5 years from needing your kit because I'm broke but will you be offering a complete RV-12/Rotax retro kit some time in the future. Sounds like a really good idea to me - and economical too in the long run. Thanks for alerting us to this up grade.
 
Yes....

We are currently just starting an RV-12 build. We will be offering a complete retro kit.

But, for those who want them now, we can build the hoses to custom measurements.

Have a great day,
Steve
 
Those hoses are cool!

I have a few questions for Tom about the hoses for the Rotax.
On the last pic with the fuel block removed is there a restriction in the fuel return line?
What would the total cost be for that mod in that same pic(compete Rotax retrofit)?
Will you have a booth at OSH with a few of these Rotax hoses there?:confused:
 
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John and David,
Right now I probably will not be at OSH. But--if you'll email me, I'll tell you anything you want! The pic that Steve posted here is of a RV12, with a slightly modified fuel pump to accomadate the AN hose ends. The original Rotax hoses are rubber, with either low pressure crimp bands. Some applications of the same engine are using hose clamps. Mine are my standard stainless teflon hose, with stainless hose ends. An AN tee, and an AN cross are used in these assemblies.
I basically copied the original hoses, so everything fits.
My email is [email protected]

Tom
 
OH yeah---that hose package is on John Jones' beautiful RV12 in Fort Worth. John was nice enough to email me the installed pics. I'm pretty sure if some of you are in the Ft Worth area, he would not mind at all if you looked at his installation.
Tom
 
Scott, don't know the answer to your question on the Facet fuel pump. Couldn't find anything in forum search either. However the elec. pp. puts out about 1.2lbs pressure and I suspect that would be sufficient to help with a more controlled off field/on field landing as the engine would be developing power and landings are usually accomplished with a closed throttle (given sufficient altitude and suitability of landing area). 3.8lbs is normal with a working mechanical fuel pump, but 1.2 may be sufficient to fly above stall speed until a suitable landing area is found. It would certainly be the first thing to try. It's a good question. Hopefully someone out there has a more definitive answer.
Dick Seiders 120093
 
I don't understand - the POH Checklist calls for Fuel Pressure before Start as 'Normal", which is - I believe 2.2 psi. My boost pump puts out about 2.7 psi before I turn the Start key (I have a separate Fuel Pump Switch - but pulling the pump fuse accomplishes the same sort of check.)

After engine start, the fuel pressure is more like in the 5.7 - 5.9 psi range.

Bob Bogash
N737G
 
I don't understand - the POH Checklist calls for Fuel Pressure before Start as 'Normal", which is - I believe 2.2 psi. My boost pump puts out about 2.7 psi before I turn the Start key (I have a separate Fuel Pump Switch - but pulling the pump fuse accomplishes the same sort of check.)

After engine start, the fuel pressure is more like in the 5.7 - 5.9 psi range.

Bob Bogash
N737G

IMHO "Normal" means anything more than zero. At this point you are just verifying that the electric fuel pump is working by it showing "some pressure". Then after start the engine driven fuel pump starts working and then the fuel pressure comes up in the green or normal range on the Skyview.;)
 
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OK - the question is -- will the 2.7 psi from the elec boost pump run the engine normally with an INOP engine driven pump???

Bob Bogash
N737G
 
OK - the question is -- will the 2.7 psi from the elec boost pump run the engine normally with an INOP engine driven pump???
NO !
I have no personal experience, but have read reports from others who experienced partial power loss on takeoff. Very unnerving! The Dynon EMS indicated low fuel pressure and high fuel flow. The bad mechanical pump either leaks fuel or ingests air or both. The pilots were able to keep flying at reduced power and returned for landing. Replacing the engine driven fuel pump fixed the problem. Theoretically the electric pump alone should be able to supply the engine with ample fuel. And I think it would if the mechanical pump was bypassed. If the aircraft had two electric pumps and no engine driven pump, there would be less chance of fuel leaking inside of the cowl or sucking air into the fuel lines. But then what happens in the event of an electrical failure?
Joe Gores
 
Is Alcohol a surprise to Rotax

In everything I have seen on the 912 Rotax recommends auto fuel, even with etoh. In fact, our service requirements are cut by 50% if we use 100 LL. So can someone tell me why they use hoses that need to be replaced at 5 years with autofuel?. I am sure that there are a number of us on this forum that drive a car or truck that is way more than 5 years old. I have not replaced the hoses on my 7 year old Nissan truck, nor have I had to clean the carb bowls. My 16 year old Nissaan Frontier is still on the road, and agin, on the same hoses. So tell me why on my $25,000 "modern" 912 do I need to do this at 5 years. Yeah, There is the old argument that a failure in the air is more significant etc. Ok, with all the cars on the road, how many do you see broken down on the side of the road each year?
I agree with earlier comment about the lawyers siping their coffee and expounding ways to sell more parts for Rotax. If the hoses on the 912 are so poor that they only last 5 years, why are they using them? None of the auto makers have this requirement, and they sell a lot more cars. Sure, they don't worry about inflight failures. But what do do think Consumer Reports, The car magazines, let alone the Feds would say if cars were dropping like flies along the road due to failure of the fuel hoses at 5 years?
Either the 5 year replacement schedule is way too conservative, or Rotax is ripping us off. I for one will monitor my engine, but I am not replacing good parts based upon an arbitrary schedule. As the NTSB and AOPA have noted, post maintenece is one of the most dangerous periods of flight. I am not going to cut into hose and replace parts with low service time due to flipping the pages on a calender.
This is my 2 cents, and as others have said, your mileage may vary. Flying is expensive enough without replacing perfectly good parts.
 
The Pap's include a fuel flow test. If the electric fuel pump passes you WILL be able to run the engine on the electric pump. That's why you do the test.
 
"I agree with earlier comment about the lawyers siping their coffee and expounding ways to sell more parts for Rotax. If the hoses on the 912 are so poor that they only last 5 years, why are they using them? "

Here's a discussion on the 5 year question - I posted on it the same way I did on here. Like you, I distrust everything about this requirement. Plus - I'm told Rotax has actually run their engines satisfactorily with 20% (or even 25%) ethanol, with no problems. The U.S. seems to be moving towards 15% ethanol - a decision just in the past week - and maybe 20% is not far behind.

http://www.rotax-owner.com/rotax-blog/item/20-the-task-at-hand-rotax-5-year-rubber-replacement

I personally feel there is a cred (credibility) problem - on the one hand, you have Rotax saying 5 years and "yer out!", and on the other hand, they spec'd, purchased, installed, and then got A.D.'d over fuel hoses that were not compatible with gasoline (nothing said about ethanol.)

Actually, altho this thread has drifted into the ethanol arena, I don't believe the Rotax 5 year requirement has been described as an ethanol problem. Rather, it may be due to - say - high ozone levels in the atmosphere - like in S. California - and aircraft that have their fuel hoses exposed to sunlight (like in say, a Trike, etc.)

Then, of course, Vans has muddied the waters with their own ethanol Service Bulletin - which doesn't say much, but seems to be 100% CYA.

Bob Bogash
N737G
 
Bob and all--
I feel the 5 year replacement on the Rotax hoses is like the old AC20-7N, which stated hose pressure tests every 100 hours, and replacement at 5 years. Now, I dont know about you guys, and some of our A&P and I&A guys can tell us (me)---who was REALLY pulling hoses at 100 hours and pressure testing them? I've done some 303 hose for some people that had 15-20 year old date codes. ( I saved one that I did in 2006 that had a date code of 1966, and was still flying).

But what I can tell you from my automotive experience is that ethanol will eventually attack the neoprene/nitril liner of a rubber hose, like those on your Rotax, and begin to form some work harden cracks. Under flexing, these cracks begin to open up, and the hose begins to seep. Granted---your plane doesnt put anywhere near the amount of hours on it that your car or truck does. Late model vehicles have a teflon, or thermoplastic hose/liner combination, that isnt affected by the ethanol additives.

Rotax, and others are being safe by recommending the hose change. Just like the old 20-7N. Rubber hose is easy to install, way less expensive than teflon hose and crimped fittings. In some cases, it may be better and less expensive to just replace the hoses every 5 years. ( I dont know what the cost is of the Rotax hose replacements). But---IMHO--teflon will out service any rubber hose out there. Yes--it is overkill on a very low pressure system, but it is the best for this application.
Tom
 
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Tom,
What would you consider the safe useful life delta between plain rubber hose and Teflon lined hose? Twice the service life (10 years)?
 
Tough question, since teflon has virtually an unlimited service life. As long as it isnt abused, abrased, or subjected to alot of heat, it generally will outlast the airframe. Rubber hose, neoprene, nitril, or those rubber based liner really should be changed out on a regular interval. Lets face it---5 years of flight time is pretty good.
One point that I will make is that teflon hose, although is pretty forgiving to abuse, it doenst like to be straighten out after being in its 'installed configuration'. Its like 303 hose in that respect. Ever seen a piece of 303 that has been on a plane for a long time---such as an oil hose? Try to straighten it out and listen. Sounds like a bowl of Rice Krispies. Teflon doesnt snap and krackle like that, but remember the liner is thin, so if you try to straighten it out, you can fracture the liner. So---if you do take one off and plan to reuse it, take care to leave it as it is.

I'd have to say that teflon should outlast a rubber hose by 5 times---so maybe 25 years? Ive seen some teflon assemblies on military aircraft with mid 60's date codes that were still flying. Great testimate to teflon---
Tom
 
This has turned out to be an interesting thread in spite of the drift to hoses and ethanol. but that's ok as we are all learning something. Getting back to the question of the fuel pump SB I believe the electric pump would keep us in the air altho at much lower power settings. Even Joe Gores kind of came to that conclusion considering the referred to takeoff power losses that managed to fly to landing. I don't believe the elec pp would satisfy full power requirements, but don't know, and hope to never find out during takeoff. To those I confused with my psi numbers sorry as I mis-spoke (Wash. DC speak for making wrong statement). My 1.2 lbs was accurate, but my 3.8 was a fuel cons. readout while taxi-ing. My normal flying psi is about 5.7 psi. I just returned from field after conducting another elec. pp. test, and the readout was 1.3 then gained to 1.5, and fell back to 1.2 as the system filled and started using the return line. Bob was right on the PAP flow test and my results were 115 sec. for one gallon. Seems to me that would be ample as it exceeds any hourly requirement that I am aware of. At any rate it raises my confidence regarding fact the elec. pp. will keep us flying well above stall speed should the mech. pump fail. Of course if the diaphragm breaks and the fuel starts coming out the weep holes other unpleasentries may occur.
Dick Seiders 120093
 
As designed, the electric pump will run the engine just fine up to rated power. The problem comes from the variability of failure modes of the engine driven pump. If the engine driven pump fails in a way that causes a heavy loss of fuel, at a higher rate than what the electric pump can over come, it is possible that only partial throttle could be used.

The majority of the engine driven pump failures that I am aware of, has been a failure mode where the pilot was unaware of the failure, other than an increase in fuel flow and/or a decrease in fuel pressure, but the engine still running normally.
 
Thanks for the input, Scott. Your pump failure comment brings to mind that a favorable point for the new pump is the dump tube keeping fuel out of the engine area in event of failure. While the possible loss of fuel is still (or could be) a factor in adjusting throttle to keep flying the dump overboard feature makes the c/o to the new pump a bit more attractive.
Dick Seiders 120093
 
After 40 hours of fight in New Blue, I had an infight failure of the mechanical pump. It was brought to my attention by a low fuel pressure alarm which was set at 2.0 psi. I didn't really know that it was a failure because the engine never skipped a beat during the next twenty minutes it took for me to get back to base. With the cowling off, I could see that fuel had been coming out of the weep hole on the bottom of the pump. Not a great amount, but it enough to render the pump inop. So barring any failure that could cause a real blockage, the electric pump is more than sufficient to keep the engine running.
 
Hey Man! Someone who has "been there and done that!"

Mucho thanks for that little tidbit, Mitch. Gives me a big dollop of confidence into this situation.

Bob Bogash
N737G
 
We've just replaced the mechanical fuel pump on G-TWLV for the latest spec pump in accordance with Rotax Service Bulletin SB-912-063UL R1.

According to the Rotax Operators Manual, the max fuel pressure with the new pump (pump serial number 11.0036 and on) has increased to 7.26 psi (0.5 bar).

The previous pump maximum pressure was 5.8 psi (0.8 bar).

The minimum pressure remains the same at 2.2 psi (0.15 bar).

On the first flight with the new pump the high pressure fuel alarm started sounding when on final approach at idle power.

I've now changed the max fuel pressure limit in the set-up menu on our SkyViews.

Our SVs were our own installation being pre-Van's SV avionics package. Perhaps Scott can advise whether the Van's supplied SVs can have the limit changed in the field or if it is locked.
 
We've just replaced the mechanical fuel pump on G-TWLV for the latest spec pump in accordance with Rotax Service Bulletin SB-912-063UL R1.

According to the Rotax Operators Manual, the max fuel pressure with the new pump (pump serial number 11.0036 and on) has increased to 7.26 psi (0.5 bar).

The previous pump maximum pressure was 5.8 psi (0.8 bar).

The minimum pressure remains the same at 2.2 psi (0.15 bar).

On the first flight with the new pump the high pressure fuel alarm started sounding when on final approach at idle power.

I've now changed the max fuel pressure limit in the set-up menu on our SkyViews.

Our SVs were our own installation being pre-Van's SV avionics package. Perhaps Scott can advise whether the Van's supplied SVs can have the limit changed in the field or if it is locked.

None of the settings are locked for Skyview. Builders/owners should be able adjust the high limit if/when they install the new pump.
 
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