Thermostatic radiator valves (why I hate plumbing 2)

[Nigel Watts]

Plumbing and I just don't seem to get on.

I have often taken off radiators to decorate behind them or, most recently, to install wires for a wall mounted TV in our modern extension. Not trusting the thermostatic valves I usually put a cap on the pipe as a precaution. Since taking the radiator off the hot water system has consistently been losing prerssure - about 1.5 bars in three for four days. I have been obsessively checking for leaks.

I found it this morning. Brown damp staining in the room below (my wife's study) confirmed the location. The thermostatic valve seems not to have an off position but a "frost protection" setting, which means it comes on below 8 degrees. The room has another radiator so later in the day (when I have been checking for leaks) it switches off because it is warm. My cap, though screwed down tightly, is leaking when the valve comes on.

When plumbers install central heating systems it should be obligatory for them to leave an instruction manual. How else is one supposed to learn about such things other then expensive trial and error?

 

[Me!]

I don't trust thermostatic, manual or lockshield valves when I take radiators off. I discovered a few years ago, when I needed a couple of caps in exactly this situation, but didn't have any, that a 10p coin fits exactly inside a spare nut that screw onto these valves. Add a smear of plumbers paste, and you can make your own temporary caps that in my experience have never leaked.

 

[middi]

Join the club. I found out the hard way same as you Nigel.

Unused or redundant thermo rad valves should be capped off if left in the heating line. I posed the same question to a plumber friend of mine regarding warnings, he replied that every plumber knows, thermo valves have frost settings incorporated.

Middi

 

[tobydog]

When we had our whole new system fitted recently (boiler, radiators and piping) the plumber got a duff batch of valves. They whistled and knocked at all hours. We finally managed to get him to replace them all at no cost and they've been fine since. I'm convinced he just bought the cheapest and it cost him but you need to do your homework and not necessarily settle for whatever they want to fit. He'll probably charge you for the best anyway!

 

[robgil]

Drain the system down if in any doubt.

 

[Nigel Watts]

I have now applied some PTFE tape and tightened the cap as much as I can. It seems to be holding.

 

[Lime]

The simple answer is that thermostatic valves are not designed to act as isolating valves.
The best solution (if you want to use thermostatic valves) is to fit an inline isolating valve as well.
The brown staining is indication of too little inhibitor in the heating system.

 

[biffvernon]

Thermostatic valves are for people who are too lazy to turn appliances on and off as needed or for those who wish to abrogate their free will, delegating choice to machines.

 

[skier-hughes]

or maybe free up time to campaign against global warming :wink:

 

[biffvernon]

Never mind radiator valves but I needed to change a tap for which I needed a basin wrench, which, curiously, I didn't happen to have, so I bought one. This morning I was ready to use it.

Instead I sent this e-mail to the good folk of Rothenberger, manufacturers to the plumbing trade.

I bought a Crowfoot Basin Wrench 1/2"-3/4" No.8.0162 from Graham The Plumbers' Merchant in Louth, Lincolnshire, UK at a cost of £6.32
I had to drive a round trip of 24 miles to get it and it took about an hour of my time.
The tool is not fit for purpose. The jaws of the wrench have not been cut correctly so that it does not fit the tap nuts for which it is designed.
Yes, I know I should take it back to the shop and get another one, but that will be another 24 mile trip and an hour wasted.
Why do you sell tools which are not fit for purpose?
Regards
Biff Vernon

Plan B was pop next door and borrow one from the neighbour. New tap is fine.

 

[Feltwell]

Rothenberger are a reasnoble brand as well (I think!). Let's see what response you get.

I informed (not complained to) English Heritage that their website was wrong for an abbey near here - I tried to take the kids there one Sunday morning as the website said it was open, only to find it shut for the winter. To give EH credit they replied quite promptly, saying they had amended their website and thanking me for the information, and they extended my family membership by 2 months and sent me a guide book to the abbey. A nice response I thought.

 

[jocelyn plummer]

We are having a lot of trouble with pressure on our combi gas boiler. If we run the heating on timed, the pressure drops when heating off, and has to be corrected to give hot water in the taps. If we run heat all the time and turn off stats in rooms where we do not require warmth, the same thing happens. The problem, we think, is that there are 5 traditional style rads ( fitted by the people from whom we bought the house), those rads have valves that are either on or off ---they are ferociously hot when on, too hot for the rooms really. When we first switch the heating on for the colder days we make sure that all stats and valve s are on full for about an hour, then we set the 4 modern rads that have thermos to our required temperature-- 2, and one of the old style rads is turned off permanently as it is not required. It seeems that we should pobably get controllable stat valves for those rads, but what a price-- about £70 each! Or, maybe, it would be better to fit a controllable stat to the boiler , cheaper I suppose and better in the long run? This is the infuriating thing about this house, the people before us did half a job when they refurbed. The boiler was 2 years old when we bought the house and, so I am told, should have had the other control, but we did not notice that until too late.

 

[Keithj]

I don't know if yours is like ours, but whoever designed our boiler knew that pressure increases when the water gets hot. There is a "pressure vessel" - a tank, probably 20 litres or so capacity, with a water container (rubber, I assume) and an air chamber. I don't know how it works, but when our pressure was going up and down in the way you describe, Marcus the plumber said "pressure vessel", changed it, and problem solved.

The tiny leaks elsewhere were a separate problem, now also fixed. The pressure stays much the same from one month to the next.

 

[middi]

The pressure vessel is basically a spring loaded " accumulator" , as the hot water pressure increases and expands between the hot and cold cycles, allowance has to be made for this increased pressure and volume expansion to be contained, hence the pressure accumulator or vessel.

If no allowance is made to alleviate for this increase in pressure, heat exchangers and other ring sealed components in the boilers etc will be at risk of pressure failure.
The " safety"pressure vessel is fitted in addition to the mandatory pressure relief valve wich comes into action only if the water is about to turn into steam due to a system failure and directed to a safe outlet usually ouside the property.

Middi

 

[Penners]

When plumbers install central heating systems it should be obligatory for them to leave an instruction manual. How else is one supposed to learn about such things other then expensive trial and error?

I have long believed that not just plumbing but entire houses should come with a comprehensive instruction manual.

When you buy a toaster, you get a 16-page instruction booklet telling you how to use the appliance, not to drop it in the bath, not to stick your fingers in it, not to place furry kittens on top of it, etc.

When you buy a house, you'll get (if you're lucky) a casual shout from the departing vendor, as they move out, to "watch out for the bathroom tap - it sticks."

When we moved out of our last house, I left copious notes about the details of running the house, local suppliers, local shopping and so on.

 

[Lime]

When I sold my last house the new owner came back to me to ask why the central heating wasn't working properly and I quote " only 3 radiators get hot".
I asked the simple question (always wise) what had he done?
He replied that before he switched on he'd been around the radiators and turned all the valves on.
That puzzled me as it was a standard water/radiator system and I never touched the radiator valves at all and then it dawned on me what may have happened.
So I asked " both sides of the radiators?"
"Yes" was the reply.
My face screwed up as I realised he'd opened the lock shield valves that balance the system and had taken hours to set up correctly.
(I recall his wife thumping him on the way out! )


http://www.muswell-hill.com/foxandco/pages/balancing.htm

 

[AMc]

When we had our heating installed the brand new pressure vessel failed almost immediately filling with water. It was apparent to the plumber as it was full of water so didn't sound right when tapped. Worth a try.

 

[Baron de Gynes]

I did that when we moved out - a pack of notes (although not as comprehensive as those left by the estimable Mr. P) giving details of how to cope with the house's foibles.

I wish that the previous owner of this rambling pile had done the same; he explained everything to me and the only thing that I was able to retain was how to light the woodburner (we came from a 30's semi with instantaneous gas...). I couldn't remember how the heating worked, how to control the hot water, where the stop-tap was, where all the fuse boards were, how they were connected to each other, or indeed WHY we have four of the flippin' things in separate areas of the house.

I managed to work out how the TRVs work, though. I must admit that when one or two required attention last year that Dr. Google came to the rescue as he usually does.

 

[jocelyn plummer]

Many deliberations on a common problem it seems. I'm just wondering if I dare go out on Thursday when OH is not working, as he is threatening to turn off the boiler and bleed all the rads---------------------then switch on again============= I'm sure there isn't an air lock, and I have checked all the visible bits of pipework, there's no sign of any leaks anywhere.

Oddly enough there have been one or two comments on our local blog about fluctuating boiler pressure in the area, so perhaps I should phone the gas board and see what presure they are giving us, and see whethter it matches the requirements for the boiler that we have --is that the right thing to do?

 

[Keithj]

Our thermostatic radiator valves are WONDERFUL. When they were fitted, we did still have to balance the system (a bit) with the valves on the other side of each radiator, but that was all done in about half an hour.

Last Saturday I noticed that the kitchen was a bit cooler than normal, and the radiator was cold apart from the bottom couple of inches. I don't know where all that air came from, but it had probably been there since the summer. I bled it without changing any other settings (repressurising the system a couple of times as I went) and all is well.

Easy, it was. Only that radiator had air in it - probably because of its position in the chain.