Towel Rail on boiler circuit

[Audio Engineer]

Hi everyone,

In my house the boiler (standard heat only) is in the garage and the flow and return run in 28mm under the first floor bathroom and into the airing cupboard across the landing where the cylinder, pump and motorised valve are

I want to put the bathroom towel rail on the main circuit, so it is on any time the boiler is running, whether it's proving CH or HW.

Am I allowed so simply tap into the flow and return with a reducing tee, or is there more to think about here?

Thanks!

 

[ShaunCorbs]

No as it’s before the pump need to do it after the pump

 

[Audio Engineer]

No as it’s before the pump need to do it after the pump

Will it make that much difference?

The flow and return are both free flowing, and there will only be minimal flow required for the radiator. My understanding was that the high pressure on the return would be enough to draw enough through from the flow side.

What's the possible outcome if I was to put it in where I'm suggesting?

 

[siricosm]

Then it would act to bypass your boiler. The pump would push (or pull) water through the rad instead of through the boiler, and it would reduce your system performance accordingly. You don't want to do anything to reduce the flow through your boiler, and it could even be dangerous if your boiler gets too little flow.

It might be possible to connect both sides of the towel rail to the flow pipe some distance apart, like they do it in a one-pipe system, but I'm guessing it would get too little flow if you had a TRV on it, or be hard to control if you didn't. Never tried it, maybe someone else can comment if that would work.

Is it really too difficult to do it properly and run pipes under the floor back from the cupboard? Depending on the layout you might be able to snake a pair of flexible 10mm copper through, which would be plenty for a towel rail.

 

[Audio Engineer]

Ah, ok, that makes sense!

A one pipe solution might work fine, if anyone can comment please feel free!

It's not a big deal to run pipe back from the airing cupboard after the pump, am I right in thinking that I'll only need to run one, as the return from the rad can just go into the return to the boiler?

 

[ShaunCorbs]

Need to run two as for the three tee rule

 

[siricosm]

If you can run pipes back, then for sure I would go that route. It is not worth the hassle to try something that might not work to save a few feet of pipe. A single pipe could work, so long as there is nothing taking off from the pipe between the boiler and the pump, in your case I presume the pump is on the flow.

I would probably go with two pipes, as it will be easier to understand for future maintenance. I would also be careful to make sure that towel rail doesn't get too much flow. Being straight off the main so close like that you will need to close the locksheild on the towel rail to a trickle, otherwise if someone cranks the TRV wide open on the towel rail it could starve the rest of the system.

 

[siricosm]

Need to run two as for the three tee rule

That is a good point. In this case he wants the towel rail running even when the heat is off, so depending how it is piped (zoned) he might have to put it where the bypass is, or would be. Is that correct?