Bathroom rads on hot water circuit (conventional system)

[Arch Panda]

I'm getting conflicting advice so I thought i'd try on here for a bit more information.
All our half landing bathroom rads are on the hot water circuit - some plumbers say they must come off the circuit and go on the heating circuit, others say they can stay. Which is right?

Background & further info here:

We have a victorian house with an interesting collection of pipe work, some left from a previous solid fuel boiler system. Last year we had the boiler & HW cylinder replaced and now have a Worcester Bosch Greenstar 40CDi Classic boiler (kitchen)& pressurised cylinder (loft).
We have 2 bathrooms and a separate WC all adjacent to each other on a half landing. We are in the process of just turning them into 2 adjacent bathrooms which means changing some of the rads around.
Currently there is a conventional rad in the WC & the hallway, a chrome ladder rail in one bathroom and a reproduction rad in the other bathroom.
We would like to leave the hallway one as, remove the towel rail completely , directly replace the WC one with a slightly larger rad and move & replace the reproduction one with a modern rad. They are all on the HW circuit and the hall & WC ones at least seem to have been plumbed in parallel as they work with the TRVs we had fitted as part of the work last year.
I believe that as we have a heat exchange system rather than a directly heated system that there is no reason they couldn't stay on this circuit but some plumbers say they must be removed others say its ok - who is right?

(it'll be a right PITA to move them over to the heating circuit as no pipework runs to this part of the house at the moment hence my reluctance to just do it)

Thanks for any help you can give

 

[Simon F]

welcome to the forum panda.
Ideally you should have separate control for hot water and radiators.
energy efficiency etc, but as its existing ...

if the rads in the bathroom have trv's then at least you can easily turn them off now that it is warmer.

 

[Roger Welton]

I personally would want them on the heating circuit, as with the high capacity coils on modern cylinders the Hw loop won't be on for long

 

[Ch4 plumbing]

If you have the time and money why not run the towel rails on their own independent circuit with its own 2port and programmer?
then you have complete control over it.

 

[Ermintrude]

Leave rads on the pipework and put 2 port at the cylinder. . Rads can run when they like and cyl safe. But this isn't compliant with part l of building regs

 

[lame plumber]

make sure the replacement rads are nice n thick coz they will corrode out with all that fresh water running through them in no time at all.

 

[solutions]

make sure the replacement rads are nice n thick coz they will corrode out with all that fresh water running through them in no time at all.

Its not a direct cylinder so that shouldnt happen they are just on the same pipework that supply the cylinder coil so system water which should be inhibited.

 

[Worcester]

As Ermi says though if you run them on the DHW, they will only be on for a very short while whilst the DHW is being heated...

Honeywell Evo rules :clap: - virtual zones where you want them, when you want them as complex or simple as you want them (and probably cheaper than re-plumbing as not all rads have to be on evo trv's you can use normal room stats as well)

Still have yet to find anything else that gets close and is so simple to install.

 

[kris]

make sure the replacement rads are nice n thick coz they will corrode out with all that fresh water running through them in no time at all.

Still Heating water just on the hw circuit, ie (coil) no fresh water lame,

 

[Ermintrude]

Still have yet to find anything else that gets close and is so simple to install.

Locksheilds with wheel head , loo roll shoved over it with some glitter and stickers and the controller ice cream tub with the same level of decoration and a few batteries for good measure?