TRVs on dual fuel towel rails - can it be done?

[Bettyboo]

Dear Plumbers

I am in the process of buying a new build, it has 3 bathrooms with undertile heating and chrome heated towel rails.

Builder has said he is not prepared to put thermosats on the rails but I have asked if I pay for them will he fit them. He has said "the towel warmers are part of the bypass to the central heating system and are required to be fitted without a TRV. In addition as they are dual fuel if the TRV did shut off there could be an unacceptable level of pressure build up and by fitting them it would nullify any guarantees to the central heating system and house insurance."

I assume as they are said to be dual fuel they run off the gas and electricity system.

I wish to be able to keep my house running costs to a minimum and so do not wish to have the towel warmers /rails on when not needed. I am conscious if they can be turned on by a switch using the electricity someone could accidently leave it on all day. Also it would be handy to have the control (when using the gas heating)of keeping the heat to a minimum or turning them off when the bathroom is unlikely to be used.

I would be interested for your thoughts on whether it is possible to safely fit and use thermostats/timers/comtrol switches.

Thank you very much for your help

Betty

 

[Howsie]

Yes it is ok to use a TRV in the bathroom. You won't be closing the lockshied anyway but if you did the pressure increase would only be 4%.

 

[SimonG]

I wouldn't use a trv on the bathroom if you are using the dual fuel.

 

[Bettyboo]

Hi Howsie
Thanks for this, still a little unclear though.
Please confirm that the TRV's could go on all the towel rails without causing heating system to blow up!
Also, would the thermostat control both dual fuel operations ie: if the electric setting had been switched on or if it was running of gas water heating system?
Is it also possible to turn the rails off temporarily?
Thank you!
Betty

 

[warrington]

It is not practical to use in bathrooms!

 

[Bettyboo]

Simon thanks for your reply, but why not?

 

[SimonG]

When you use the electric elements you should shut the valves so that you are not trying to heat the whole htg system.

 

[Bettyboo]

Ok Warrington, but why not? It would be good to have some control as if the electric setting has been used it could accidently be left on all day, don't see the point when house is empty all day

 

[SimonG]

If you do use the electric elements you want them on a fused spur and a timer. They're not cheap to run.

 

[aqualogic7]

1 not good practice to use towel rail as by pass should use by-pass valve, as this eliminates accidental shutting of by-pass towel rail.

2. Duel fuel towel rails are fine to use in bathrooms, the idea is when heating not on i.e. summer switch to electric heating element in towel rail and isolate one valve of towel rail to stop circulation.

 

[ADM360]

One of the problems with fitting a TRV to a towel rail is that once you've covered the towel rail in towels the TRV could become covered, thus thinking it's hot and closing down! resulting in a cold towel!!

 

[Howsie]

When you use the electric elements you should shut the valves so that you are not trying to heat the whole htg system.

That doesn't happen. Urban (plumber) myth.

 

[SimonG]

That doesn't happen. Urban (plumber) myth.

Is that right, must have imagined it the last time I saw it then

 

[GQuigley67]

if the boiler has a built in automatic bypass valve then there will be no need for a bypass radiator, if not an automatic by-pass valve can be fitted to the system to remove any need for by-pass radiators

 

[Howsie]

Is that right, must have imagined it the last time I saw it then

Do you have thermal eyes?

No need to shut the valves to IMHO. I've two at home and don't have this problem and have never witnessed it. You'll get circulation in the rad but not the whole system.

 

[GQuigley67]

do you have a room stat ?? or are you having one installed ?? reason i'm asking is generally wherever the room stat is situated the radiator in that room will not have a TRV and will constantly be on as the room stat controls the temperature, this also acts as a by-pass

 

[SimonG]

Do you have thermal eyes?

No need to shut the valves to IMHO. I've two at home and don't have this problem and have never witnessed it. You'll get circulation in the rad but not the whole system.

Yep, along with x-ray vision and being able to leap tall buildings with one stride

You haven't felt it, I have, can only report what I have witnessed, same as yourself.

 

[ADM360]

Also as this is new build I would expect a built in bypass, if not then an auot bypass fitted, don't quote me on it but it ask's for one on the bench mark! and is it not a requirement of building regs that all rads have TRV's? and as it is new build the use of heat leak rads is an old idea! also it you have 3 bathroom it will be zoned with seperate time and temperature control!!

 

[Nat]

if the boiler has a built in automatic bypass valve then there will be no need for a bypass radiator, if not an automatic by-pass valve can be fitted to the system to remove any need for by-pass radiators

In addition to this part L building regs say you you should have a proper bypass built into the system. Gate valves or bypass rads are not allowed as they are not considered to be energy efficient. If it is a new build you should be having a bypass valve fitted if the boiler requires it.

 

[Bettyboo]

do you have a room stat ?? or are you having one installed ?? reason i'm asking is generally wherever the room stat is situated the radiator in that room will not have a TRV and will constantly be on as the room stat controls the temperature, this also acts as a by-pass

The room stat is downstairs in the hallway. Don't think there is a rad in hallway(can't be sure). I think there are thermostat controls on the rads. There are no rads in bathroom just "chrome heated towel rails" (as described in brochure.) Builder last described them as "towel warmers". No TVR on rails/warmers. There is undertile heating in bathrooms which can be set by a timer - not sure about temperature control.
Gas fitted heating system with pressurised hot water cylinder. A back electric immersion heater is fitted to the hot water tank. Solar panels on roof said to contribute to approx 10% of the total energy usage.

 

[warrington]

Where the radiator valve is often covered with a towel,clothes,curtain,etc., It is better to remote sensors. Because of the heat in bathrooms when you use , and towels or clothes on radiators affect the trv, because it was not practical to put trv, bathroom towel radiators used to be used as heat leak rad.

 

[stevetheplumber]

That doesn't happen. Urban (plumber) myth.

i agree if i could heat a system from one little element id be a millionaire

 

[Bettyboo]

If you do use the electric elements you want them on a fused spur and a timer. They're not cheap to run.

I suppose you mean the towel rail when it is run on electricity? Any idea approx how much?

 

[Osp]

The wattage of the electric element can be anything from 100W to 1000W depending on the size and model - the wattage of yours will be stated on a label somewhere. Around 250W to 300W is fairly typical, which is very roughly 3p or 4p per hour to run. So £1 per day if left on all the time.

Another thing to mention about the TRV when running from the central heating is that when your bathroom gets lovely and warm because you are having a bath, the TRV will turn the towel rail off. It's a thermostat - that's what it is for!

Of course the best way to avoid wasting money is to turn either the electric or the rad valve on only when you need it.

 

[AWheating]

it depends on what the main use of the towel rail is? heating the room then fit a trv. your builder is incorrect about the rail being a bypass, your system should have a automatic bypass designed into it. Sometimes its in the boiler but i always think its good practice to fit one on the system even if the boiler has one.

 

[Bettyboo]

i your system should have a automatic bypass designed into it. Sometimes its in the boiler but i always think its good practice to fit one on the system even if the boiler has one.

Is it a regulatory requirement to have an automatic bypass on new systems?

 

[Nat]

Is it a regulatory requirement to have an automatic bypass on new systems?

Yes. See my earlier post regarding part L building regs.