Ok guys and gals of STW I need your help and advice. I moved intoa new to me (1930s) house in feb. Luckily we’ve had a mild summer and winter and so the gas bills haven’t been too bad. Now when he weathers turned chilly the heatings on and were cold. Heating comes on at about 4:30pm and the front room isn’t warm until about 9pm ish.

So the rad in the front room (furthest away from the boiler) only got hot at the top. I took this to be possibly a blocked rad. Took it off and flushed it through. Got some black crud out of it and back on. Still the same. I then gave up and asked a heating “engineer” to pop round yesterday. He diagnosed the problem as a sticky trv valve. Drained the system and fitted a new one (plus a few more downstairs) the water while draining down the system didn’t look too black or anything so I thought nothing else of it.

Nowthen heres a bit of additional info that may be useful

A few months ago I removed a rad from the bedroom. Accidentally (not having had drain off valves before) I drained some of the system off instead of the rad. We had 2 days of no heating till I called an engineer out as the system was air locked. He diagnosed the problem as a loop above the diverting valve as shown here. So this time I asked him to fit a vent so we could bleed it and refil

See in this photo.
https://plus.google.com/u/0/photos/108267992033991783465/albums/6101913436219624961/6101692336468939074?pid=6101692336468939074&oid=108267992033991783465

Ok so this was done and se start filling up the system again after the TRVs are installed. Can we refill it? Can we buggery. After half an hour of faffing it was decided to “back fill” using a hosepipe to one of the radiator take offs. Another half hour + later we had all the rads with some water in them but it took another hour for the boiler to fire and warm the rads though. Like there was a massive air lock in the boiler and it was tripping out.

Once it got going last night we had a warm radiator in th front room about 2 hours after the boiler kicked in. this is the best its been. However the engineer is suggesting we now try a new pump to see if we can improve things. This makes sense to me but what are your thoughts?

So now we have heating! Yay! But I still need to be able to take the rads off etc to decorate. At the moment im not confident we can do this.

So looking at our hot water system and its got me baffled. Thisis how I think tis looking.
https://plus.google.com/u/0/photos/108267992033991783465/albums/6101913436219624961/6101916247516068930?pid=6101916247516068930&oid=108267992033991783465

but ive got no idea what this valve is for?
https://plus.google.com/u/0/photos/108267992033991783465/albums/6101913436219624961/6101913821000899714?pid=6101913821000899714&oid=108267992033991783465

more photos here but it’s a right pain not knowing whats what.

https://plus.google.com/photos/108267992033991783465/albums/6101913436219624961

can anyone shed any light?

The heating engineer was almost on the verge of lets rip it all out and start again!

Help!

I am not a plumber. Probably I should stop typing now!

Another half hour + later we had all the rads with some water in them but it took another hour for the boiler to fire and warm the rads though. Like there was a massive air lock in the boiler and it was tripping out.

Could it be your heatexchanger in your boiler is limescaled up and is getting to temp and not transfering it to the heating water… hence slow to warm up heating and tripping out boiler as it senses over temp? Did you put limescale inhibitor in the water when you filled the system?

ive got a bottle to put in tonight as it was only filled yesterday i thought id let it settle first

Once it got going last night we had a warm radiator in th front room about 2 hours after the boiler kicked in. this is the best its been

have you balanced the system?

worth doing if some rads are miles from the boiler and some are not.

OTOH you might just have terminally gunked up pipes leading to the problem rad.

but ive got no idea what this valve is for?

that’s a branch from the cold feed into your hot water cylinder

it most likely feeds the bathroom cold taps (and maybe others).

doing this (rather than taking cold direct from the main) gets the hot & cold at the same pressure/flow – you’d need this if you fit a thermo mixer tap to the bath.

the valve is isolated btw.

what would the effect of opening it be? vs closing it?

the rads are not balanced. I guess it makes a bit of difference.

maybe the thing it used to feed is removed?

or it could be used for a shower pump cold feed

hi guys

ive had another look and this is more representitive of the system.

https://plus.google.com/u/0/photos/108267992033991783465/albums/6101913436219624961/6102309642662970098?pid=6102309642662970098&oid=108267992033991783465

ive balanced the rads (not properly) to get a roughly even distribution of heat around the house.

the boiler only kicks in for 1 min at a time before switching off for several mins and then back on again. Im presuming that theres no flow from the cw tank as the pipe is magnetic at the join. however the rads and hot water are hot.

no idea what that valve is for. ive cracked it open a small amount and it doesnt seem to make any difference (its one of these inline isolating valves.

I still need to be able to take the rads off etc to decorate

I’d whip the pump head off to check, if you are lucky there will be isolation points above and below the pump and they will turn…
My last issue was a clogged impeller, hence having checked the entire system and seen the pump turning through the rear port on the pump head I was still getting low flow rates.
Fitting a new pump head was a five minute job and made a massive difference to the heating effectiveness. The old pump was left soaking in descaler and is now back in the spares box as a working pump.

I wouldn’t bother removing the rads to decorate either, if you can’t get a radiator roller behind then the little paint pads in this set are excellent. Might not get all the way behind but far enough so you can’t see the old colour, or you could just attached to a piece of batten or something to extend it.

Rather than an air-lock, or pump failure, I’d be suspecting a blocked/partially blocked pipe somewhere.
How much black muck came out of the rad you took off?
Was it ‘lumpy’ or just dirty water?
Lumpy would almost confirm a blockage.

Dont beleive the hype about powerflushes – they may work in extreme cases, but for most people, they are not worth the cost, a normal ‘fll up with system cleaner, run for a week, then flush out’ will be better, and cheaper.

My 30+ year old system was completely blocked up with Limescale but a bottle of Fernox DS-40 cleaned it all out in a week, made a right mess as I had rust coloured foam frothing out the over flow pipe for a week!

I drained my complete system and put two tubs of sentinel X800 in the header tank and fitted a sentinel eliminator inline filter on the boiler return earlier this year. (other filters are available)
The system is now hot all over, and I have removed about two mugs full of scale/debris from the filter.
Also agree with taking the pump head off and checking that, mine was restricted with scale and debris as well.

Andy

The idea of the valve is as a bypass, not ideal and those type of valves are a nightmare on heating systems (pretty poor valve in general but it is all the merchants seem to keep)
You need to get the cold feed and vent arrangement correct. Ideally it should be as close to the suction side of the pump as possible and on a horizontal section of pipe. The open vent is first then the cold feed closest to the pump. The tees should be no more than 150mm apart, and preferably both pipes should be 22mm in diameter, although it was common practice to run the cold feed in 15mm. Both pipes should rise continually to the feed and expansion cistern, with the open vent terminating over the cistern but above the water level. It should rise to a minimum of 450mm above the cistern before turning back in a reverse U shape. The cold feed should come out of the tank about 25mm from the base. The water level should be set so that there is enough to cover the cold feed by about 40mm this should allow enough for the expansion of the heating water (it will expand by 4% over the temperature range of a heating system).
You have been the victim of some lazy plumbing where they can’t be bothered or don’t know how to install a heating system correctly.
I would also recommend checking the pump particularly the impeller and the inlet outlet ports. Also check the valves are turned on fully.
And balance the rads (mail me at timATj-twren.eclipse.co.uk and I’ll send you some notes on rad balancing)

cheers for the tips.

I flushed the system out with some sentinal x800 (left it in for a few days) and then ran water through it from the header tank. this was all well and good until the level dropped too low and i couldnt refill the system again. que 4 hours of me faffing about. In the end i filled up a fire extinguisher with water and used it to blast down the cold water feed. this seemed to free the blockage i suspected in the CW feed for the time being and the system refilled.

with the rads opened i couldnt get any heat at all in the downstairs rads. The ones in the upstairs bathroom were warm however. Ive managed to balance the system of sorts to try and get some relatively even heat distribution in the house. But its far from warm. The rads are warm to touch but not hot. Im not sure why this would be. My only thinking is lack of flow? possibly a pump issue?

replaced the pump last night and initial thoughts are its a little better…..

not great though.

with the rads opened i couldnt get any heat at all in the downstairs rads.

I get this after I drain and refill, seems to be an airlock somewhere which just goes after a few hours of running the pump.

Could it be your heatexchanger in your boiler is limescaled up and is getting to temp and not transfering it to the heating water…

Before christmas I had a few weeks of fun and games with my (combi)boiler.Initial diagnosis was the diverter valve ,then a gunked up secondary heat exchanger and then blocked pipes.British gas were kind enough to offer a magno flush for the best part of a grand! In the end I held firm and had the boiler stripped and the primary and secondary heat exchanger washed out.That cost £160. The boiler now works a treat.

You can’t wash out limescale, it has to be dissolved using something acidic…

Fernox DS40 is good, but probably will eat through an Aluminium heat exchanger….

FF – yes my mistake – sorry, mine had black metalic gunk that blocked mine up.
I caught a builder type draining down through the safety/relief valve – the dunderheed.