Radiator to heated towel rail.

[TerryH]

Probably a stupid question, but as a novice some reassurance would be appreciated.
I have a job to replace a bathroom radiator with a heated towel rail. The customer assures me it is run from the domestic hot water circuit.
The question is.....
Is it enough to turn off the heating and drain the hot water cylinder in order to allow me dry pipes to work with? As the radiator is fed from the domestic hot water and is separate from the heating circuit, I asume this will work and I will not have to drain down the c/h circuit.
Many thanks for your help,
Terry.

 

[newbie1]

do a search but not sure they should be run from the domestic hot water circuit ime sure a few days ago there was a debate

 

[MarkB]

Terry,

When the customer says that it runs off the DHW do they mean that it comes on then the cylinder is heating?

Is it possible that the radiator is tied into the boiler primaries? This means that the rad will get hot whenever the boiler is on and is not dependant on the position of any zone valves fitted.

There has been another thread similar to this recently http://www.ukplumbersforums.co.uk/p...owel-rail-plumbed-into-hot-water-circuit.html

If it is an indirect system then it is likely that this is the case and you will have to drain the CH / boiler circuit.

Mark.

 

[TerryH]

Thanks for the help.
I was unsure about having the water from a radiator mixing with the domestic hot water, but I think probably Mark is on the right track here. It is an indirect cylinder.
The logic is sound, Mark's explanation means the rad is separate from the dhw but will always be available when the boiler is working, which coincides with DHW heating times (I think!).

I shall nip across and look at the link you have left and do some more research.... I don't enjoy drain downs, they're time consuming and costly. They always seem to leave air locks too (although I found the bottom up re-fill method pretty reliable). This would only need a partial drain down but I may resort to a few cans of freezer and do it that way, once I have made sure the heating has been off for several hours.
Thanks for your help, appreciated as ever,
Terry.

 

[NickH]

If this rad is fed from the DHW circuit then what it means is the feeds to the rad are tee'd of off the flow and return from the heating coil (primary's) in the hot cylinder, when the cylinder is being heated the rad gets hot. Therefore you will have to drain the heating system , which includes the cylinder coil. Alternatively you could try a plugging kit which can be very useful although not always 100% effective.

Without meaning to be rude i do find it slightly worrying that your planning to work on a heating system which you seem to have very little understanding of. A radiator would never be fed from the actual hot water supply from the cylinder, its a basic misunderstanding of how the system works and indicates to me that you dont really have the knowledge/experience to start messing around with peoples heating systems, sorry but you can do some serious damage if you dont know what your doing.

 

[Logic]

I will happily stand corrected on this matter however I don't believe it need be necessary to drain the entire heating system in order to safely replace the radiator. If there is a point of potential drainage purely for the pipework servicing the coil (revolvers) then it should be possible to drain only that and proceed with your work. (Uncertain how common drains are on revolvers?)

*Edited to add; I should have noted that the above goes with the proviso that flow to the CH circuit and revs. is shut off. I imagine there's apt isolation for the heating sys. Obvious but I felt I should include that. There's some dependency on how client's system is set up here.

 

[garry]

hi terry i share the concerns of the others however if you are going to do this job then work safe it my take a bit longer to drain all the systems but i would perfer you to drain down then try and do short cutts if ur not sure, am guessing you have no insurence (no affence if you have) but if you drain down and make a mistake its not going to cost you if you try shortcuts and make a mistake it could be very costly just work safely and take your time.