Central heating - anyone know a bit?

DorsetDude

DorsetDude

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Live in a bungalow with 8 radiators. The system is "open" I believe its called. i.e. has a separate water header tank in the loft.

The problems I have is firstly that the bathroom rad, which is a tall towel rail type one, loses water fairly quickly and I get air gap at the top of about 10". When I bleed it, it drains too much water out of the header tank and the boiler then refuses to fire up and I have to struggle up into the loft with a bucket of water trying to cross the 10" thick insulation without going through the ceiling, to top up the header tank. (fitting some decent loft flooring above the insulation probably a good plan)

Why does the tall radiator lose water so quickly? Can it be prevented?

Yesterday I noticed that while all the other radiators were on ok, the hall radiator was totally cold. Turned out that was empty of water as well. I started bleeding it but didnt reach any water spouting out and again the boiler has refused to fire up this morning so its up into the loft again later.
Is there anything I can do to prevent the water loss in the system and/or get a self filling header tank put in in the loft a bit like the main water tank with its ball valve thing?

Also might there be air moving around the system and maybe settling in the taller radiator, if so how do I get rid of it all?

I have got a reliable gas engineer/plumber so can call him if needs be but bleeding and topping up tanks I can handle just about.

Many thanks.
 
Your header tank should already be self filling thats the main advantage of an open system. However what may have happened is you've introduced air into the system so it may need to be refilled.

If your losing that much water I would be checking for leaks. the water in the CH system Should be constantly moving around the system and through the boiler (when on) thats how it heats the water. the reason why you have air in the top of your towel rail is because its more than likely the highest radiator in the house (air rises) the radiator in the hall being cold may be due to it no being blocked so no water can move around it.


Its worth getting the plumber out
 
Regarding the need to manually top up the tank in the loft - the ball valve 'float' in the header tank might be corroded so that it can't move - just hangs in mid air.

Can't understand why the boiler doesn't fire up unless the header tank is completely empty. In this case air must be drawn into the system, which is why you have to keep bleeding the rads. Definitely worth getting a plumber in I reckon.

AL
 
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Al1944 said:
Regarding the need to manually top up the tank in the loft - the ball valve 'float' in the header tank might be corroded so that it can't move - just hangs in mid air.

AL
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Yeah think Im gonna need to get that sorted, save me a lot of hassle. It might even be the root cause of the problem although where water is disappearing to in the first place is a mystery.
 
Agree with everyting mattyg says, I have a closed system (combi) and my bathroom radiator will go cold at the top over time as it's the highest point so where the air gets trapped.

At my old house which had a traditional open system, as the water got hot in the central heating it would expand and leak out the overflow on the header tank, which ran out a pipe under the eaves and made a puddle outside the back door.
 
I would go round every radiatio and bleed them and top up the tank all in one go, maybe have a mate sat in the loft so you can pass the water up, then monitor it.

look at all the radiator valves, any gunk arround them? any stains on the carpet?

the water loss may be the boiler also any leaks there?
 
The boiler could also be over pressure causing the pressure relief valve to open to release pressure. When this happens especially with older systems little bits of crud can stop the valve from closing properly which will cause water loss
 
mattyg said:
The boiler could also be over pressure causing the pressure relief valve to open to release pressure. When this happens especially with older systems little bits of crud can stop the valve from closing properly which will cause water loss
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if the P has an open system I don't think it will be preasurised as a combi?

dunno but it could be a heat exchanger leak.
 
Mr Bump said:
if the P has an open system I don't think it will be preasurised as a combi?

dunno but it could be a heat exchanger leak.
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Ha ha I need another coffee. I knew that.. Although there "May" be something on the hot water tank
 
if its loosing a lot of water then my money would be on the boiler or pump or it could be hidden pipe work.
 
Bleeding radiators would negligibly alter the water level in the header tank. It could appreciably reduce the pressure in a closed (combi boiler) system but this is vented so not relevant.

Have you really not got a ball valve in the header tank? I find that very surprising (unless you bought my last house where I didn't get round to fitting one before I sold irt!).


Steve.
 
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Steve Smith said:
Bleeding radiators would negligibly alter the water level in the header tank. It could appreciably reduce the pressure in a closed (combi boiler) system but this is vented so not relevant.

Have you really not got a ball valve in the header tank? I finf that very surprising (unless you bought my last house where I didn't get round to fitting one before I sold irt!).


Steve.
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i think as someone said earlier it might be fubar or non fuctional or possibly even never fitted.

pictures :-)
 
I'd defo check the header tank for a (non-working) ball valve, it should really have one, but if the installer wanted to save money .....

  • Get the plumber to fit a ball valve (if not already fitted)
  • Then
  • Check for leaks
  • Then
  • Fit a self bleeder on the bathroom towel rail/radiator.
  • Then
  • Check the the water for Inhibitor (fernox or similar) and apply if required
  • Then
  • With everything off bleed all the radiators
  • Then
  • Board the loft :)
PS The header tank should also have an overflow pipe fitted.
 
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My father used to be a central heating system designer. He once told me about a system in use in the 1960s and into the 1970s which had a header tank without a ball valve. The tank was usually positioned in an upstairs cupboard and it raised an indicator flag to show that the level was getting low and needed to be topped up.

I doubt that there are many (any) of these still in use though.


Steve.
 
I think john-oh has summed up exactly what I need to do, but thanks to all for input. It is odd where all the water goes though, might have to get the plumber in and ask about it, get him to check it over. Will check the ball valve on the header later.
 
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or you could fit a really massive header tank :-)

like an old septic tank.
 
Steve Smith said:
My father used to be a central heating system designer. He once told me about a system in use in the 1960s and into the 1970s which had a header tank without a ball valve. The tank was usually positioned in an upstairs cupboard and it raised an indicator flag to show that the level was getting low and needed to be topped up.

I doubt that there are many (any) of these still in use though.


Steve.
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That would be the old "Servowarm" central heating system. The Nottingham area seemed to have loads of these systems fitted. These did in fact have just a small header tank which had to be manually filled, I have taken many a one out and fitted a small plastic tank complete with Ball Valve & overflow. john-oh suggests a self bleed valve, here again I have fitted many of these, but the problem with these is that after a time they let the air out but then do not shut off completely and so leak water. I would suggest the main thing as has been said is to shut the system down , then bleed the rads and for the present keep filling the header tank as you go along. There is the possibility that if you bleed the rads with the pimp running you will be sucking air in.
 
Well, into the loft last night and sure enough, the header tank for the heating has a ball valve and this was jammed in the up position and very stiff (Ooh matron). So I forced it down and let the water refill the tank til it cut off. Carried on bleeding the radiators. Once Id finished and fired everything up the bathroom radiator refused to get hot so I went round closing off all the other rads trying to force water through it. Nothing seemed to work. In the end I just left it for an hour and when I went back to check it was then fully hot.
Bleeding the rads I got black gunk at first then a very pale reddish sort of water coming out, maybe this is the fernox stuff mentioned above.

So I think a new ball valve assembly would be a good idea and find out where all the missing water goes to.

Cheers all
 
:plusone:

Sounds like a full drain down and flush could be in order before refilling with an added inhibitor. Now would be a good time of year to do it - while plumbers are relatively quiet and when you don't need the CH. Don't forget to have a bath/shower before the plumber starts the work just in case it turns out to be more than a one day job!
 
Nod said:
:plus1:

Sounds like a full drain down and flush could be in order before refilling with an added inhibitor. Now would be a good time of year to do it - while plumbers are relatively quiet and when you don't need the CH. Don't forget to have a bath/shower before the plumber starts the work just in case it turns out to be more than a one day job!
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If you do go for a 'flush' be prepared (depending on age of installation) for changing the odd radiator due to leaks.

It certainly sounds like you could do with a proper plumbers check out (not BG they just try to sell you a powerflush regardless).

You've got to have a new ball valve anyway - the expensive bit is getting a man on site, get him to check it all out whilst there.


-
Edit -
He might suggest mods such as an air separator or magnetic filter (after a clean out).
 
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Sounds like you might have a lot of rusts and rubbish buils up as above a good flush out
 
What's all this talk of plumbers? Do it yourself. There's no rocket surgery involved!


Steve.
 
Steve Smith said:
More likely a sign that you should have used Fernox!


Steve.
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When I say it had a tinge, it looked clear coming out of the bleed valve, but as it built up in the jug I was using you could see there was a colour tinge to it. What colour is the fernox stuff?

While Im pondering getting a plumber in, is it ok to just fit a thermostatic rad valve in one room only? Might get him to do that as well. I dont need the bedroom as warm as the bathroom/rest of the house so was gonna get one for there.

Cheers
 
there will defo be a tinge as the radiators are just pressed steel so will rust a bit over age a realy good flush will take some of the sediment out as well.
 
DorsetDude said:
While Im pondering getting a plumber in, is it ok to just fit a thermostatic rad valve in one room only? Might get him to do that as well. I dont need the bedroom as warm as the bathroom/rest of the house so was gonna get one for there.
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That will work fine but it's better to put them on all of the radiators and do away with the room thermostat.


Steve.
 
Steve Smith said:
That will work fine but it's better to put them on all of the radiators and do away with the room thermostat.


Steve.
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Hmmm, wouldnt the boiler then end up pumping hot water round(bypassing) a load of closed off radiators because it doesnt know not to keep heating water because all the radiators are closed. But anyway, I'll stick with one for now if I do.
 
DorsetDude said:
Hmmm, wouldnt the boiler then end up pumping hot water round(bypassing) a load of closed off radiators because it doesnt know not to keep heating water because all the radiators are closed. But anyway, I'll stick with one for now if I do.
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No. Its internal thermostat will switch itself off when it reaches temperature. The pump will over run for a few minutes but it's o.k. as it's supposed to do that.

EDIT: I just remembered that you have an older vented system rather than a combi. In which case, you would need to check the boiler to see if it can be used that way.

With a combi boiler, it was standard practice to put thermostats on all radiators and not have a roomstat until the building regulations changed to insist on a pointless room thermostat.

Some traditional systems needed a plumbed in bypass but I usually got round this by putting thermostats on every radiator except the one in the bathroom.


Steve.
 
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Steve Smith said:
My father used to be a central heating system designer. He once told me about a system in use in the 1960s and into the 1970s which had a header tank without a ball valve. The tank was usually positioned in an upstairs cupboard and it raised an indicator flag to show that the level was getting low and needed to be topped up.

I doubt that there are many (any) of these still in use though.


Steve.
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Was what I would say.

When looking at buying a home in the 70s I came across many header tanks without top up feeds. They were quite small and found in the highest point to get the gravity needed. Saw them mainly in flats. Putting them in the lofts of bungalows was short sighted. With insulation below them as a later add on would leave them liable to freeze.

Closed systems with condensing boilers are seen as the best choices these days but the placement of the 'overflow' for condensate is important. They can freeze during winter blocking run off so the boiler will stop from firing if it detects the condensate not running off.

Just had to have the heat exvhanger on my 6yo Ideal boiler replaced...... started a savings fund to get it replaced witb a Worcester or Valliant one.

Good luck to OP, it may be time to look at a closed system with a more efficient boiler. Long term you will save money. Trouble is you may need to re-pipe a 1 pipe system to a dual pipe system to get a balanced flow and economy.

Quite a few older houses used single pipe systems so more expense .

S
 
Steve's advice about doing away with the room thermostat is very poor advice. A sure way if increasing your fuel bills. Thermostatic radiator valves and a room thermostat is the way to go, with the radiator in the room where the room thermostat is, left without a thermostatic radiator valve.
 
chphotos said:
Steve's advice about doing away with the room thermostat is very poor advice. A sure way if increasing your fuel bills. Thermostatic radiator valves and a room thermostat is the way to go, with the radiator in the room where the room thermostat is, left without a thermostatic radiator valve.
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That makes more sense to me, although Id probably leave the bathroom one "unthermostatted" as well.
 
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