Closed Off Radiator Valves in order to heat water only - seepage from valve on boiler

CBYR1983 · 15-07-2011 08:32PM #1

Hey

Have an old boiler and system - single zone for rads and water, there is a hand valve on the feed from hot press to upstairs, but downstairs branches off between boiler and hot press.

Have been using the immersion to heat water and it's costing a fortune. Said I'd try heating water with the boiler.

I've turned off all radiator valves (relatively new, TRVs), and I've turned off the hand valve for the upstairs in the hot press.

However, I am seeing some water seeping from a valve on top of the boiler (could this be an automatic air valve?) - not much, but I've never seen this before in the past when all the rad valves were open.

So I'm wondering now should I stop this - could I harm the system?

The valve on the boiler sticks out and has a number of small holes dotted around it. Small droplets of water appearing on it when the water is cooling down.

It's an open system.

sullzz · 17-07-2011 10:42PM

Perhaps take a pic of the valve your talking about , by the way your describing the valve it sounds like an old type of safety valve

CBYR1983 · 17-07-2011 11:09PM

Pic attached.

From looking at some websites I think it is an automatic air valve. When I peer closely through the holes I can see what looks like a coin. It's propped up on one side. I imagine it should be sitting level, and much lower. Maybe air had built up in system over the time it was not in use (c 2-3 months) and when it was turned back on it blew.

I reckon it's 1 1/2". Do they still make these? Could plumber use a reducer of some sort in order to fit a modern one. Not much space though with thermostat to the side of it, the ones I've seen online look much bigger.

Any idea of possible cost to replace. Does system need to be drained? (No blasted draincock on system either, first reason why I'd never think of going near it)

Billy Bunting · 17-07-2011 11:17PM

It's a safety valve/presure relief valve, and if its been blocked off with a coin you seriously need to get in a plumber ASAP.

CBYR1983 · 17-07-2011 11:26PM

Billy Bunting wrote: »

It's a safety valve/presure relief valve, and if its been blocked off with a coin you seriously need to get in a plumber ASAP.

Not a coin really

, just whatever is in the valve is busted! A flat circular piece of metal! I would have thought this raises up with air/pressure, then drops back down once released. No longer dropping back down.

Why it blew I don't know, dirt maybe? Any ideas on cost of replacement/process.

I've used a heating guy in the past but like to know what I'm up against. Great old boiler otherwise, can't invest in a new one.

Billy Bunting · 17-07-2011 11:35PM

PRV's around €10 and easy enough to fit once drained.

If its leaking its venting pressure, you need to be sure and have the system checked because if it was faulty and went BANG!! you'll need more than just a PRV. :eek:

It actually looks to me as if it's been tightened down at some point to stop it leaking.

sullzz · 18-07-2011 07:23AM

CBYR1983 wrote: »

Why it blew I don't know,

I'm guessing that because of how old your safety valve , that your hearing system is also very old and probably gun barrel pipework , you mentioned that it's an open vented system , vent is probably sludged up among the line somewhere and as you closed all rads , the pressure had nowhere else to go but at the safety valve , I could be wrong but it's just a guess

CBYR1983 · 18-07-2011 01:42PM

Could be it sulzz, but I'm surprised it never went before.

Spoke to a plumber today. He reckons the boiler may be too big for just heating water to the cylinder. It is a big one. Reckons I should not use it for just that. Here I was thinking that it would be ok. I thought turning off the rads was a normal thing people did in the summer if they have no independent hot water feed from boiler.

Given the expense I'm going to incur now replacing the valve, I probably would have been better off using the immersion. Lesson learned.

Any ideas what I should expect on pricing. System will likely need to be drained down.

sullzz · 18-07-2011 03:30PM

If it's not leaking when heating is turned off , you might be ok , if you have a balancing valve on your coil on your cylinder you could try opening that fully or if not you could try turning your pump down a speed , but remember exactly what you do so you remember to put it back the way it was when you are using your rads again

Sparkpea · 20-07-2011 09:26PM

if its a F&E tank I'm guessing something may be capped off up there to stop expanding then causing the PRV to blow/leak water (just a quick read at this thread and haven't read all replies)

CBYR1983 · 07-08-2011 10:35AM

CBYR1983 wrote: »

Hey

Have an old boiler and system - single zone for rads and water, there is a hand valve on the feed from hot press to upstairs, but downstairs branches off between boiler and hot press.

Have been using the immersion to heat water and it's costing a fortune. Said I'd try heating water with the boiler.

I've turned off all radiator valves (relatively new, TRVs), and I've turned off the hand valve for the upstairs in the hot press.

However, I am seeing some water seeping from a valve on top of the boiler (could this be an automatic air valve?) - not much, but I've never seen this before in the past when all the rad valves were open.

So I'm wondering now should I stop this - could I harm the system? The valve on the boiler sticks out and has a number of small holes dotted around it. Small droplets of water appearing on it when the water is cooling down.

It's an open system.

Got this valve replaced - but is there any chance the vent to the expansion tank in the attic branches off the upstairs circuit that I closed off with hand valve? Would seem incredibly bad but I'm starting to put 2 and 2 together and get 5. Looks that way. System probably went in during the 60s.

Dardania · 08-08-2011 07:42PM

Is it oil or gas? If oil, you could get a dual tariff electric meter, and heat the immersion at night with a timer using cheap rate electricity. Make sure the cylinder is insulated however...

The reason I say is it oil is because there are no standing charges with oil compared to gas, so it is no skin off your nose if you pay slightly more in electrical standing charges.

Otherwise, you could look at the oil boiler: is there a way off lowering it's heat output?

Buford T Justice · 10-08-2011 10:19AM

CBYR1983 wrote: »

Got this valve replaced - but is there any chance the vent to the expansion tank in the attic branches off the upstairs circuit that I closed off with hand valve? Would seem incredibly bad but I'm starting to put 2 and 2 together and get 5. Looks that way. System probably went in during the 60s.

Its possible they used the lines upstairs to run to the F&E tank yeah, and closing the rads up there isolated the OSV pipe causing the leak.

If you can follow your pipework around and see where it goes it'll answer your question. Ideally it should be running up to the attic direct form the hot press.

Closed Off Radiator Valves in order to heat water only - seepage from valve on boiler

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