Help Wiring A Honeywell Rf2 To A Ideal Mexico System Boiler

[gram1980]

Hi guys & gals,

Wonder if anyone can help with my problem

Fitted a new honeywell RF2 pack 3 Heating controller with wireless room stat & cylinder stat for my neighbour a few days ago, which replaced a honeywell ST699B programmer.

The boiler is a Ideal Mexico Super 2 RS50 which i believe is wired as a C plan but without a motorised valve, its gravity HW with a pump on the CH which is located in the boiler itself. There was no cylinder stat fitted either.

There is no wiring centre as such, just a couple of connector blocks which were behind the old programmer to joint the original room stat cable. I replaced it for a wireless system due to damage to the stat cables.

The attached photo shows the wiring diagram for the boiler, which has a gas valve operated via a thermostat in the boiler.

It was wired as it shows and I connected the HW line to LB at the boiler and the CH line to LP along with neutral & earth too the supply & the pump.

However upon setting up the system the gas valve failed to operate when either HW 0r CH or both were called for, the pump however was running on both. I then linked out the 2 lines & that operate the gas valve when either HW or CH was called for. However now when the HW is switched on the CH also activates.

It does say in the honeywell manual that for gravity HW systems a suitable valve should be fitted however thats not an option.

Any ideas how i sort this out for them ?

Cheers

Graeme

http://s1327.photobucket.com/albums/u662/GraemeSears/

 

[gram1980]

Cheers for all the help guys

 

[user 15807]

Hi, Slightly sarcastic Cheers for the help there! Frustrating when no answer I know.

I am not familiar with the boiler but sounds like you wont be able to control the heating without hot water because you need a feed to the pump and boiler to run the heating. If you link the pump and boiler you get CH every time the boiler starts.

You will have to fit a valve or accept that the HW & Ch will have to run together. As far as I can see, to run heating alone you can do this by turning on DHW. to get heating you would have to turn on DHW & CH so pump runs from CH and boiler is fired by DHW feed.

Sorry no easy way out I can see.

 

[gram1980]

Cheers for that was a bit annoyed lol. Spoke to Honeywell who confirmed what you've said & I suspected. Got a plumbit coming to fit a valve this morning.

Regards

Graeme

 

[Steve3948]

Well this is not a SYSTEM boiler but more a bog standard boiler that just requires a trigger switch live to fire it.

I assume if you have gravity hot water you have 4 pipes from the boiler (heating flow/return) (hot water flow/return), so to control both hot water and heating separate a S-Plan with a zone valve on each would give you total control of each, heating valve would open with room thermostat and hot water would open with cylinder thermostat, in both valves you would use the auxiliary contacts to fire the boiler and pump together.