Brand new noisy CH water pump

Shuggieg

Hi

Recently had a new WILO Gold RS50 water pump installed by registered fitter. The pump makes a loud gurgling sound when running, sounds like air and water being stirred up. Have bled the radiators and the bleed screw on the pump several times. Also a small vent at top of pipe on join between pump and tank. Only a small amount of air coming out of 2 upstairs radiators but pump still noisy. The noise reverberates around the house and is quite intrusive. Called the fitter out again to look at it but he says it is just system noise and we have to live with it. He has already power flushed the boiler and fitted a filter to catch any debris in the system. He says the only thing left to do is power flush the whole system (at a cost of £400) and says there is no guarantee of it getting rid of the noise. Read several forums where the answer is replace an old pump but this one is brand new! Any suggestions please?

roger196

Are you bleeding the rads / pump when the CH is off? If you do it when on, you draw more air into the system.
Is there inhibitor in the system. You can check whether there is enough by using a test kit.
Are the pipes either side of the pump supported by pipe clips.

Shuggieg

Hi Roger

Yes I switch system off before venting pump and rads and on suggestion on another forum I left it off for a while before venting but still noisy.
Yes he put inhibitor in when flushing the boiler.
I can't see any pipe clips, the pump seems to just be set within the pipework which runs into the tank on one side and down through the floor I assume to the boiler and rest of the system.

Thanks for your prompt response

wellused

I'm no expert but I have bled a central heating pump before by unscrewing the screw in the middle of the face of the pump part way, don't unscrew it too much or it will come right out and beware any water which escapes is very hot, wrap a towel around it an just crack the screw a bit don't worry if the screw does come right out the water doesn't shoot out or anything it's just a trickle. As I say I'm no expert and this was a few years ago so pumps may have changed.:o

Shuggieg

Thanks well used, I have been doing as you suggest as part of the venting/bleeding process but no improvement in the problem.

southcoastrgi

it could be a number of diff things, wilo pumps aren't the best pumps in the world, was your old pump set on a lower speed ? the vent & cold feed could be connected wrong allowing air to be drawn into the system, & finally just powerflushing the boiler & not doing the whole system is a complete waste of time & money because if you have sludge in the system most of it will be in the rads so as soon as you run the system all the crap will go back into the boiler again, yes he has fitted a filter but he should have done the flush correctly in the first place, i suggest you get a second plumber to look at it.

Shuggieg

Thanks Keith, yes the old pump was fairly quiet on low speed but was not pumping enough and when it was turned up to high speed the bearings were noisy, hence need to replace. The logic for powerf lushing the boiler only was to be able to use stronger chemicals and sort out some problems we had with the boiler.

How can I check if the vent & cold feed could be connected wrong?
rgds

southcoastrgi

http://www.google.co.uk/imgres?q=cold+feed+%26+vent+layout&hl=en&biw=1280&bih=661&gbv=2&tbm=isch&tbnid=yaJz0lDKLtXFbM:&imgrefurl=http://www.partsarena.co.uk/baxi/System/DATA/Dx/DS1/installation/2041/I01-2041/I01-2041.htm&docid=FcnY4OHuUFh9nM&imgurl=http://www.partsarena.co.uk/baxi/System/DATA/Dx/DS1/installation/2041/I01-2041/Image4566.gif&w=860&h=562&ei=uGeBT6j-CInP0QWmx5iVBw&zoom=1&iact=hc&vpx=423&vpy=263&dur=10884&hovh=181&hovw=278&tx=160&ty=97&sig=110232423798080267978&page=2&tbnh=135&tbnw=207&start=19&ndsp=20&ved=1t:429,r:6,s:19,i:126

cold feed & vent should be on the negitive side of the system ie inbetween the boiler & pump this should prevent "pumping over" but if the vent is not high enough before it goes into the top of the tank then air can be drawn in, as a guide the pipe should go at least 12" above the height of the water level.

i'm guessing that you had scale build up in the boiler, if you don't mind me asking how much did he charge you to flush the boiler ?

Shuggieg

Hi Keith, thanks for that update, yes I have found the similar diagram in my instruction book. when I recalled the guy out after fitting the pump he checked this and found it didn't meet the spec so added a section of pipe onto it to comply with diagram.

We have had a series of problems with the boiler over a year involving no less than 4 different plumbers/engineers each saying the last one didn't know what they were doing. Now the feedback I am getting on the web is he possibly doesn't know either! I am using these forums to try and become a more informed purchaser of plumbing services and your help is appreciated.

Don't know how much the power flush cost but that plus fitting the pump and a Magnaclean filter was £362 + Vat. He is local to you in Southampton, you may know him.
Rgds

Shuggieg

Hi Keith,

Been trying to send you a PM but they are not going out to you. Will try again tomorrow.
regards
Hugh

Shuggieg

Hi

Following advice on this forum and others I have continued to bleed the rads which are still getting trapped air. Now about 3 weeks and no sign that it is improving. Is it possible that air is getting in somewhere and I am just wasting my time? I switch the system off before I bleed the air from it.

regards
Hugh