Noisy Sureflo Water Pump

[Tincataylor]

I have a problem with the Sureflo water pump in our Nuevo which perhaps someone on here has an answer to. The old pump was getting a bit noisy so I purchased and fitted a brand new one to be on the safe side. Its performance on the cold water system is perfect and as soon as the tap is closed it stops immediately. However, on the hot water system it continues to run once the tap is closed for about 5 seconds and ends with about another 3 seconds with a really loud pulsing noise, and it feels like it’s trying to shake itself loose.

I have consulted the book of knowledge and can confirm that there are no blockages in the system and that the pump filters are clean. I have also tried adjusting the pump cycling adjustment screw and it makes absolutely no difference where I set it to the pump operation. Looking at the pipe layout diagram I am at a loss to see what it is between the hot and cold pipework that is making a difference unless there is a large air lock in the water heater and it is the pump trying to compress this air that causes it to run on when the hot water tap is closed. I can find no reference to a bleed valve at the top of the water heater.

Any bright ideas would be much appreciated.

 

[Jaws]

I have a problem with the Sureflo water pump in our Nuevo which perhaps someone on here has an answer to. The old pump was getting a bit noisy so I purchased and fitted a brand new one to be on the safe side. Its performance on the cold water system is perfect and as soon as the tap is closed it stops immediately. However, on the hot water system it continues to run once the tap is closed for about 5 seconds and ends with about another 3 seconds with a really loud pulsing noise, and it feels like it’s trying to shake itself loose.

I have consulted the book of knowledge and can confirm that there are no blockages in the system and that the pump filters are clean. I have also tried adjusting the pump cycling adjustment screw and it makes absolutely no difference where I set it to the pump operation. Looking at the pipe layout diagram I am at a loss to see what it is between the hot and cold pipework that is making a difference unless there is a large air lock in the water heater and it is the pump trying to compress this air that causes it to run on when the hot water tap is closed. I can find no reference to a bleed valve at the top of the water heater.

Any bright ideas would be much appreciated.

Impossible to be sure but almost certainly air in the boiler or feed pipes thereof
Some systems can be a total bitch to get bled completely.. and yes, a bleed valve in the top of the boiler is def something they should all have in my opinion

 

[Beemobile]

I had a new pump fitted last year and my hot water tap did the same (mixer tap) I couldn't get it sorted out, bled system down totally and started again, it didn't sort it out, I guessed it wasn't a big deal and left it at that but it's annoying, can't help you I'm afraid but I share you problem.??

 

[funflair]

Impossible to be sure but almost certainly air in the boiler or feed pipes thereof
Some systems can be a total bitch to get bled completely.. and yes, a bleed valve in the top of the boiler is def something they should all have in my opinion

I thought you needed air in the top of the boiler as a cushion when it warms up to stop it over pressurising, that's what Alde say anyway.

Martin

 

[Jaws]

I thought you needed air in the top of the boiler as a cushion when it warms up to stop it over pressurising, that's what Alde say anyway.

Martin

Maybe for the Alde system ( maybe for all systems as it does make sense ) but any air in our Truma and it just does not perform at all well !

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[Tincataylor]

I thought I would bump this thread and bring you the latest developments in the hope that it may help one of you, or that one of you has the magic answer. Having consulted a motor home engineer he came up with a list of things that he "thought" might be the problem but he admitted he did not "know" the answer.
Therefore I decided to apply some Deb'n logic to the problem and after studying the pipework layout in minute detail I determined the following. The hot water outlet of the Truma Ultrastore boiler incorporates a push fit elbow to join it to the pipe and a screw and gland arrangement to attach the elbow to the outlet on the boiler. This elbow also incorporates a valve to allow air into the system so that it does not become "locked" when draining down. A complete waste of time in my opinion as opening any tap achieves the same effect. Any old hoo I have replaced the elbow fitting to be on the safe side. Before putting the whole thing back together I hatched a cunning Deb'n plan and using the plastic tube of a biro as a sleeve I attached the cold water inlet to the boiler directly to the hot water outlet pipe, thus bypassing the boiler from the system altogether. The result is that the pump runs and stops perfectly every time (hurrah). From this I have determined that the problem is definitely something in the boiler.
I have relayed this information to the Truma technical people who could not be less interested if their life depended on it and all they would say is there is no way the boiler can have air in it, but they did helpfully add they had no idea what the fault could be.

By now you should all be bored to tears with this, but any bright ideas really would be appreciated,

The Tincas

 

[TerryL]

I found that a hot water pipe was knocking on the panel it passed through. Bit of old sponge to make a grommet, noise gone.

The pump always runs a little longer after turning off the hot as against the cold, I'd guess because it's actually refilling the boiler so has a bit longer run.

These things are often stupidly simple.

 

[Raul]

On my propex malaga it says it’s designed to trap some air to allow for expansion when it heats up.
After the pump, I fitted a expansion vessel ( 1l fiamma) , and it helps for smooth operation of pump.
I’m going to fit another one right before the boiler, that would cut the stop starts even further. This will help with air locks as well. Eventually they will clear away with use, and pressure from the bladder.