Honeywell power head Vs my CH system.

Hi all.

I have a central heating / hot water problem funnily enough ! Here's the cast of characters : Honeywell 3 point power head. Grundfos pump (UPS 15-50x18 Model C)... new last christmas. Potterton EP2002 Controller and a Potterton Netaheat Electronic wall hanging boiler. Problem. I'm no tech head so here is my view of things. Room stat is always on max as we have thermostatic rad valves and cylinder stat is on 140f and system has run fine all summer. Obviously we just simply hav'nt run the CH system. Well, we fired up the CH about 2 days ago and all we heard was a horrible mechanical clicking (Not boiler as this was/is on for HW). Traced the sound to the power head. When being turned on the switch (?) inside was rotating being driven by a tiny gear, but seems to be slipping/resetting back to original position repeatedly. In my infinte wisdom I jammed the switch lightly in the open postion and everything worked fine ... until today. (PWNED ! guilty!!) Today we swtitched the HW on and heard a horrible screaming/gurgling sound. Fiddled with switch and sound has dissapeared but now the pump does'nt vibrate (as though it is'nt working) and just gets hot. we also can't hear any water moving. So is the powerhead dead ? If so do I just replace the motor part or the whole thing ? Btw, we did a test thing which is described on the net where we turned room stat to min and cylinder stat to max, put switch in auto and urned in the CH. The boiler fired up but no obvious working pump.
Help.

if your pump is physically getting hot but no water movement I should say you have got a burnt out pump, seing as tomorrow is Sunday I would suggest you go to Q & B and get a new one. they are very easy to change, but it will need bleeding (as you would for a radiator, but use big screw in middle of pump) and before you remove old one see which way it pumps and put new pump in same direction (pump has flow direction arrow)

The valve motor sounds as if it has stripped the gears, this is a common fault. You can get replacement motors from Screwfix. They are just fiddly to replace.

Are the pipes either side of the pump hot? if so it's pumping water. My view is pumps should not vibrate anyway and you only hear water going round if the pump is running fast and (often) there is air in the system. It may be the pump is siezed and can be freed. If it had burnt out it would not get hot as no current would flow. (Then again I could be wrong here)

oilman you are right, wrong choice of words by myself, instead of burnt out i should have said on its way out. the pump will get hot if the motor is jambed, but if this is the case the pump will eventually burn out

A further thought. You say the pump was new last Christmas? These pumps last for decades in a clean system.Does your system need a clean? When did it last have inhibitor added?

breezer said:

I would suggest you go to Q & B

Click to expand...

Do you drive backward to Q & B or forward to B & Q

Sorry,got bored tonight good night

LOL !! ... Q+B !! Riding a CBR backwards would be kinda hard I guess....

Thanks guys. As it turns out the pipes either side are warm ... ish.

I'll check again in the morning. Screwfix on the web ? I'll check.
Oh, and could you provide a link on how to use an 'inhibitor' ? what is that ?

Sorry, I should have been more explicit. The "inhibitor" is a corrosion inhibiting chemical. Available names are Sentinal, Kamco, Fernox, Tower etc. etc. These are very similar to each other, and unless someone tells me different they are all molybdate solutions. They stop corrosion by coating the metal parts with molybdenum based molecules and so corosion doesn't occur. To be effective the loose material in the system must be cleaned out or you just prevent the sludge from corroding - not much use. It is best to powerflush the system with an acid cleaner.

There will probably be views that this shouldn't be done for one reason or another as it may cause system leaks. GOOD!!! find the leaks while you're looking for them and don't let them find you. A sound system will not leak, if it leaks just fix the leaks then you have a sound system.

screwfix are on the net they are http://www.screwfix.com

as for q & b they are related to besco, the supermarket if i was to type it as it should be that would be free advertising, but you knew who i meant though

I wouldn't disagree with much of the above , except that pumps can be absolute b***** b********* to change. Since it was done last Christmas it might be easy but it depends how it was done. And Screwfix.

Pump: If the isolating valves are quarter turn allen key operated things they might well leak all over the floor, so you'll have to drain the system to change them. The big nuts on the pump can become impossibly difficult to undo - in some cases they have to be split. One way round that is to undo the allen screws which hold the body of the pump onto the bit with the pipes, and remove the body. You have to change for the same make, broadly speaking. If that's the way it was done at Xmas you may well have to do the same cos the big nuts will be much older.


Sometimes pumps stick and can be freed off:
If you undo the big centre screw from a pump (weeps water) you can either see the end of the pump shaft which should be turning - (test/turn with a small screwdriver) or the screw bit stays connected in which you just twist that to turn the shaft. In latter case you would be able to feel the shaft spinning by sort of prodding with the bit you've got hold of, if you follow.

Screwfix do not sell the Honeywell 3 port valve head!! Visit a boutique de plomberie on your manor. there are a few types, check the number on the end. If there is NO little bump on the top of the head, you will have to change the whole valve, ie having got the water out. Bit of a pin in the botty though as others have noted, you're going to need decent drain points in working order so you can clean your system out.