Pumping over into F&E. Cant find the cause.

[markbebb]

Hi

I inherited a 10yr old system. It was pumping over when I moved in and sludged up. The water was orange so I presume pumping over for some time. I have drained it a couple of times, & cleaned it out but still have the following issue:

Only when CH & HW is on at the same time the system pumps over into F&E. If I turn the pump down from 2 to 1 it's ok. I beleive the system has also had a fairly new vale for HW/CH. I dont think the boiler has been looked for ages either.

Couple of things to note: Boiler stat is on it's lowest (not sure if it's working thought) and cylinder stat seems to work ok.

What could be causing this?
Will having the pump on 1 damage anything?

Many thanks
Mark

 

[ChrisR]

Will having the pump on 1 damage anything?

No.

Problem is pipework layout, and/or a blockage:
(finding a pic).........

 

[JohnD]

did you wash it out with plain water or use a desludging chemical?

 

[ChrisR]

See FAQ 51

 

[giblets]

Sounds like you could possibly have a restricted cold feed connection to the system or maybe an incorrect pipework layout. Does the vent pipe extend at least 450mm above the water surface in the feed tank?

 

[Agile]

Hi

I inherited a 10yr old system. It was pumping over when I moved in and sludged up. The water was orange so I presume pumping over for some time. I have drained it a couple of times, & cleaned it out but still have the following issue:

Many thanks
Mark

Orange or reddish is a sign of current oxidisation taking place. After several months it turns black.

You must properly clean out the system and solve the pumping over.

One way which I have always found works when I have done it is to convert to a combined feed and vent.

I get the impression you are being very laid back about this. Be aware that on a system that is pumping over the rads can get blocked up within days!

Tony

 

[markbebb]

im not being laid back and take this seriously, but have only been in the house 2 months and the first thing I did was flush the system throught with chemic, which I left in for 3 weeks.

Is it a possibility that the pump, which is also fairly new is too powerful, hence turning the speed down to 1 has resolved the issue?

 

[Agile]

The system can block within three weeks and faster than a slow treatment can respond.

In any case a can of chemical is immediately defeated by the dirt being produced in the first day or two.

There is an obvious fault on your system. It should be able to work without pumping over on any pump speed.

Tony

 

[markbebb]

I read the FAQ chris and one of the fixes is to simply turn the pump speed down. This appears to have fixed it for now (down from 2 to 1).

Is this a workaround because of an underlying fault or is it a genuine fix? With the pump being new (and incorrectly wired in as it was permanently on beleive it or not) I was wondering if higher setting combined with a mucky system could cause the issue?

 

[Agile]

If your car has severe vibration at 60 mph as a result of a wheel needing balancing then just driving at 30 mph is not going to fix the underlying problem!

Your heating has a problem!!!

It needs to be fixed! As have already explained the pump should be able to work at ANY settin g without pumping over.

Tony

 

[weareleeds]

Depending on make of boiler & condition of system rad valves etc you may be better off sealing system after doing a powerflush

 

[DP]

While reducing pump speed to lowest has cured pumpover, you may now find rad do not heat up properly. You may still get pump over when only HW is zone is active.

Plumbing is definaterly an issue. Get that fixed and pump over will be no more. Chances are a gravity hot water system ahs been converted to fully pumped without plumbing alterations.

 

[markbebb]

So it seems I have issues with this system thats about 11 years old. Im renovating the house and am wondering if it would be better in the long run to change this system to a combi boiler. Instant hot water appeals to me with a young family.

Reading the pages, one of the things to be aware of is lower flow rates for hot water. Just how low are these? Are we talking 20 mins to fill a bath here? I just had a plumber in who dropped my 22mm cold feeds from the loft and HW cylinder to the bath to 15mm and the flow is terrible. Partly my fault for buying a nice continental tap on 15mm feeds, but I thought he would have told me it would be pants.

What kind of pressure would I get at the taps on a combi guys?

thanks

 

[seco services]

you'll get good mains pressure

 

[JohnD]

but less flow

"Instant" hot water is available when you have a cylinder full of it and just have to turn on a tap.