baffled... hot water not reaching radiators

[madm]

HW fine. Boiler fine. CH not!

Two separate valves; both motorised and working. There is no balancer valve...

Stats working and controller working.

Forced system to pump hot water around CH; removed motors from valves, manually selected CH with no H, forced both thermostats to power pump and fire boiler.

Pipe vent on feed above pump and before valves (by HW cylinder) gets very hot. as does pipe into HW cylinder. Pipe for CH starting to get warm but much cooler below valve.

Opened all downstairs rads to try to get flow (closed all upstairs rads). Hoped that some rads (or even just one) would get hot, but no.

None of the pipes at the radiators are getting warm, let alone hot.

Water is getting back to boiler as the over-temp cuts it out after a while.

Left system running all day.

Help?

Why is the water that is circulating not making any pipes warm?

 

[Registered Gas Man]

Err the boiler is heating the hot water cylinder? Water taking easiet route seems a reason from your description.

Try turning hot water off and heating only on; then get back to us.

 

[madm]

Have tried turning HW off and CH on. Removed motors and turned valves into position manually.

Boiler working, pump working, circuit selected. Some air is gradually reaching the bleed above the pump (1/2" per day?). The boiler is noisy sometimes, but not each time that it fires up.

None of the pipework (other than at the boiler and at the pump/valves in the aiing cupboard) is getting warm.

Water is circulating.

How can this be?

 

[madm]

Another update...

There seems to be a fairly regular (every few seconds) gurgling noise, rather like a greyhound farting, that I can hear if I put my ear on the lagging on the pipe to the HW cylinder. I presume that it is actually some air returning fom somewhere on the CH circuit as the HW is off.

If the air continues to clear at this rate, some radiators might be warm by Christmas.

Any ideas on what the problem is or how I can speed the clearance of the air lock up (if that's what the problem is)?

 

[MANDATE]

It does sound like a airlock and the best way I found was to remove a radiator and run off some water from each valve. the airlock gets trapped and can't move along the pipework and opening a valve removes the resistance. Then when the system works ok, replace the radiator.

 

[PEDANTICVINDICTIVEMAN]

Check cistern in loft is full, scratch bolllockks, check all rad valve are open fully, scratch arrsse, fit new pump and check isolation valves havent collapsed into off position, bleed all air release points, pick nose, wash hands, if no joy phone a cowboy and tell him you have allready completed disgusting habit parts and only need heating fixed, this will keep the bill down.

 

[DP]

PVM you have a way with words.

 

[madm]

Thanks for your help.

The cold feed tank was fine.

The pump is fine.

I tried shuting down all rads and bleeding back either way through one thaht I thought was near(est?) the pump/cylinder/valves to try to shift what I think is an airlock. Not fixed.

I shut off all upstairs rads and opened all downstairs ones. There was still an occasssional gurgling noise, which seemed to be downstairs. Not fixed.

Today I drained the top floor rads down through the boiler, bunged some high strength DS in the header tank and refilled. Set system to CH only manually and spent an age letting air out from above the pump. I don't know whether it's fixed yet. Just taking a break and I thought that I'd give you an update.

Once again, thank you for your help and keep the ideas coming.

Oh, and I've done all the personal hygiene things too. Oops, almost wrote thongs!

 

[Slugbabydotcom]

rather like a greyhound farting

That threw me a bit ..... Now I have to hunt about for a greyhound then get it to fart before I can give a proper answer. Do you have any other similes that I can relate to?

 

[kevplumb]

a gentleman of asian origin
dropping his guts

 

[canusmellgas]

you havent by any chance taken the pump off and put it back pumping the reverse way .??????its not puling air down from the f+e

 

[madm]

Case solved!

A dose of DS helped a lot.

One of the radiators is very slow to bleed, but perseverance and juggling of valves paid off in the end.

Thank you for all your helpful suggestions.

The greyhound is an experience... just nip along to your local dog track.