Dual fuel towel rails

[ban-all-sheds]

Thinking about having a dual fuel towel rad in the bathroom - am I right in thinking that when the electric element is being used the valves should be closed to isolate the rail from the rest of the CH network?

Essential?

Ideal?

If only ideal, and I don't, how bad will the problem be, which I guess I'd hit, of trying to heat all the water in the CH via the little immersion element? The bathroom is upstairs if that makes a difference.

 

[kevplumb]

dont think it makes any diff ban as long as the pump isnt running

 

[DRM]

I think it would be essential to leave at least one of the isolating valves open to allow the heated water to expand safely into the central heating system.

 

[breezer]

I wonder.

never had one / fitted one, does it heat the water or just a part of it which is never in conact with the water?

 

[kevplumb]

its a little immersion heater in one leg of the rail heats the water

 

[breezer]

oh, thanks

 

[ChrisR]

They aren't that little - some are 2 ft long. From 250 to 900 Watts. Leave both the valves undone - you only use them when the heatings off anyway. The rail could burst when the water heats if they're shut.

Some have thermostats built in. None of them last really long so make sure its easy to drain the rail, and get it off the wall.

They heat the top down, usually enough convection to warm most of the rail

 

[ban-all-sheds]

I think it would be essential to leave at least one of the isolating valves open to allow the heated water to expand safely into the central heating system.

The rail could burst when the water heats if they're shut.

My mistake - I misread the brochure (Acova) - it does say to only shut off the flow valve.

you only use them when the heatings off anyway.

Yup - but I wouldn't use mine only in the summer. We don't run our heating for long periods, except when it's very cold, as we don't like the house as warm as most people do, so we would want to use the electric function during times of the day when the CH is off, via use of a timeswitch, so closing the valve would not be an option.

I too can't see that it would be much of an issue as long as the pump wasn't running, but I should check. Plan B would be just an electric rail, but I'd rather not.

 

[ban-all-sheds]

FYI - this was part of the reply I had from Acova:

The immersion heater is designed to produce a maximum water temperature of
70 degrees. If the immersion heater comes on whilst the central heating is
working, and if your water flow temperature is above 70, it will think that
it is malfunctioning to dangerous heating levels and the fuse within the
element will "blow". We do have dual energy elements that have a safety cut
out function that will come into operation, and wil simply need resetting to
operate again. But the simple DE PACK or similar unit will be "history".
Most boiler flow temperatures are 82 degrees in the UK, with condensing
boilers coming down to 75 degrees.

So I'm glad I asked them.....

 

[ChrisR]

SO am I! I didn't know about them things. The simple cheapie heaters around 250W just heat water, regardless. Usually the TR can lose more than that so there's no problem, you just get a hottish top half to your TR.
If the heating comes on it spreads the heat about but HW tends to stay at the top.

I've got to replace one which had a 700W element, now bust, and have a 3ft 900W one. Scratching me chin I am.