2 rads only hot when hot tap/shower turned on!

[coldinthemorning]

Hi

Have just moved into a new house. After bleeding, all radiators work fine except the towel rads in each bathroom.
Both valves are turned on, there is a trickle of water when bleeding screw turned, no sound of any air escaping.
The only time they ever heat up is when I have a shower, or turn the hot water tap on!
Has anyone ever come across this before? Is it a case of being plumbed incorrctly? Ay ideas for how to sort?
Many thanks

 

[Bahco]

Is it a case of being plumbed incorrectly?

Could be, follow the pipework back from the rads and see if they are on the heating or hot water circuit.

 

[Bamber gaspipe]

Not uncommon to have the radiators or (towel rails) in bathroom plumbed in to the Hot water side of the heating/hot water circuit. That way you have nice hot fluffy towels in Summer when heating is off. Aren`t you spoiled.

 

[kevplumb]

The only time they ever heat up is when I have a shower, or turn the hot water tap on!

think about it boys some clown has connected them to the dhw supply

 

[Bamber gaspipe]

Nothing unusual about that with an open vented system. Is it a Combi??

 

[kevplumb]

you are missing it not the boiler side the taps side

 

[Bamber gaspipe]

you are missing it not the boiler side the taps side

The `taps` side on an open vented system are connected to the hot water supply from the Hot water cylinder. If it`s an open vented system usually this incorporates a mid position or three port valve. Hot water only/ Central heating only or both. In Summer with heating off & Hot water only selected at the programmer you will still have hot towel rails in bathroom if they have been plumbed in to the hot water side of the system.

 

[kevplumb]

The only time they ever heat up is when I have a shower, or turn the hot water tap on!

explain that then please

In Summer with heating off & Hot water only selected at the programmer you will still have hot towel rails in bathroom if they have been plumbed in to the hot water side of the system.

yes on the boiler side the only time they will get hot when you turn a tap on is if they are connected to the cylinder feed to the taps or the op is running a fair bit of h/w off which he hasn't told us i do know what a heat leak is fitted enough of them on solid fuel

 

[Bamber gaspipe]

O.K. Kev no need to get out of your pram about it. My point was it was not unusual for the rads/towel rails to be plumbed in to the hot water side of the circuit. More information from OP required. What`s your diagnosis?

 

[kevplumb]

that they are connected to the dhw supply

as a heat leak rad is normally fitted before the three port valve so it is always open

as you say a bit more info from the op wouldn't go astray

 

[Rob]

Must have been done on purpose to use a copper towel rail. unless they got lucky!

 

[Timmyturtle]

Sounds like a disaster
Plumbed in to the same pipe that supplies your hot tap ...oh dear DiyNOT!
Its wrongly plumbed if it ONLY comes on when a hot tap is opened