New controller advice please

B

benholme

Hi,
I have recently moved into a house. There is an existing heating and hot water system with only very basic controls. I would like to have the option to have hot water without heating, a decent controller and different room temperatures at different times of day.

I have a wall mounted boiler in the kitchen. There is a basic mechanical time clock here supporting on/off twice a day. In the hall is a thermostat. Upstairs next the hot water tank has a thermostat which does not appear to make any difference. Next to the tank is a pump and a motorised valve.

The only way I can get hot water without heating is to turn down the thermostat in the hall. I am not sure if the pump runs when only how water is requested, any easy way to check?

Anyway, I am after a new programmer which will allow me to have a greater degree of control over the hot water and heating. I am aware that I cannot easily have heating without hot water. I also want to replace both thermostats as they are calibrated in Fahrenheit only (I only understand Celsius).

I have looked at a wireless controller with integrated thermostat from Honeywell (CM67-RF-NG). It looks to be a great unit, but as far as I can see there is no option to control the hot water at all. I am after some advice as to how to what type of unit would be best for me.

Thanks in advance for any ideas.
 
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Check the plumbing allows you to have hot water and central heating operated separately - look up how your valve works. The there is two ways you could go :

Option 1 - replace the clock with a two channel programmer and replace the thermostats with similar centigrade ones.

Option 2 - keep the current clock to run the H/W. Bypass the clock and feed the room stat as always on and replace the thermostat with a programmable thermostat. The programmable thermostat will then give you complete control on the CH including dfferent tempratures at dirrerent times ( if you get the right one - about £45.)
 
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The CM67-RF will cost nearer £100 than £45.

The temperature scale doesn't matter, nor do the numbers. If it is too cold, turn up the stat (or put a jumper on), if it is too hot turn it down (or remove your jumper). You had better get used to this soon, as in a few years fuel will be soooooo expensive.
 
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benholme

Thanks for the replies so far.

My system has a valve and a pump. The valve has a water inlet and one outlet. How can I tell if its fully motorised or spring return?

If the system is pumped heating and gravity hot water am I right in thinking its Y-plan? If both hot water and heating are pumped and the valve enables/disables heating, what system is it?

Thanks again
 
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You can tell if the pump is running, by listening to it or touching it. if it has the usual multi position speed switch on the side, you'll definitely hear a difference when you change the speed.
You say you have a two port valve on the hot water cylinder, controlled by the cylinder stat. So it sounds like you have gravity feed to the hot water, with the wall thermostat controlling the boiler and pump. You can rewire this to give hot water without heating.
A fully pumped system is supposed to be better because the heat transfer rate is higher, so the cylinder heats up quicker. I'm not sure if that makes it any cheaper to run, though.
Sounds like you want to update the controls, so you could consider
Put TRV's on all rads except living room
Put new wallstat in living room
Replumb to fully pumped and add another 2 port valve to supply heating section and add an automatic bypass in case both valves shut when boiler running.
Consider splitting the heating into zones if the house is largish (another 2 port valve!). Each with it's own wallstat.
Change programmer to 2 channel type (or 3 channel type if 2 heating zones with non programmable stats - not necessary if using programmable stats as they have built in timers).
Add an electric immersion for summer use, on a timer and change to dual rate electricity to get cheaper hot water.
It's a lot of work
asairing cupl
 

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