CH and HW

Hi, with my heating / water system I have to have the HW and CH on for my rads to heat up. Is this normal - been asking around and people have said they can get their rads on by just turning their CH on.
My hot water is fine when just the HW is on and the boiler light comes on.

If I switch just the CH on, my rads get warm for 5 minutes and thats about it, nothing more and the boiler light never comes on - not sure if its meant too.

I have a potterton boiler in my kitchen under the work surface and a grundfos pump next to it which has a switch on the left hand side in the middle possition.

My system works fine but not sure if I should have the HW on when I am just wanting CH

I do general DIY and a bit of plumbing, if the pump had to be changed I would call in the experts but as I say my system does work I'm just curious to see if I can have it working more effeicently.

Thanks

It all depends on what type of system you have.

I worked on a Thermal Store today. It had two pumps, and the HW has to be on 24 hours a day to keep the store at temperature.

When you require Central Heathing, you turn the room thermostat up/set the clock to ON and it sends power to the CH Pump, taking heat from the thermal store and dumping it in the radiators...

To better diagnose what heating system you have we'll need the following;

Make & Model of boiler
You've said Potterton - Potterton what?

I gather you have a Mid Position valve, so likely a Y Plan system, but we'll need to know what else you have.

A Pump, a cylinder, a room thermostat? cylinder thermostat? what clock/programmer? what options does it give you etc. etc.

To make most 'systems' more efficient, usually you are best to simply improve the insulation in your property. As apposed to getting a new boiler.

Get some insulation in the loft and cavity, and insulate your cylinder & all visible pipework, leaving anything like valves uncovered.

Hi thanks for the response here is some more info.
The boiler is a Potterton Kingfisher MF rs 50
The pump is a Grundfos UPS 15-50 by the looks of the writing on it and has a three position switch, the positions are marked I, II and III and its on the middle one.
The boiler is in the kitchen with the pump.
There is a clock/program timer in the kitchen which is a potterton P2002. It let me select either HW, CH or Both.
I have a room thermostat in my living room.
Upstairs I have a cylinder in a cupboard that doesn't have any controls on.
We have a radiator in every room both up and down and most of them have the trv valve so we can control the temp of an individual room.

We have added the extra insulation to the loft to 270mm and have had cavity insulation done - The pipes in the loft were insulated too.

To be honest we just want to be sure we are not wasting money by having the water on when we only want the heating on.

Thanks

gas01 said:

The boiler is a Potterton Kingfisher MF rs 50
The pump is a Grundfos UPS 15-50 by the looks of the writing on it and has a three position switch, the positions are marked I, II and III and its on the middle one.
The boiler is in the kitchen with the pump.
There is a clock/program timer in the kitchen which is a potterton P2002. It let me select either HW, CH or Both.
I have a room thermostat in my living room.
Upstairs I have a cylinder in a cupboard that doesn't have any controls on.

Click to expand...

Am I right in thinking that you have recently moved into the house?

If:

1. there are no controls on the HW cylinder, i.e a thermostat

View media item 10596
2. you don't have any motorized valves,

View media item 5946 or View media item 11762
3. there are three water pipes connected to the boiler.

Then you have a pumped heating, gravity HW system.

With this type of system you can have the HW on by itself (summer), but in the winter both CH and HW have to be on.


There are two solutions:

1. Add extra controls 2-port motorized valve and cylinder thermostat) to convert to a C Plan (cheaper)

2. Convert to full pumped. (more expensive but more efficient)

I have lived in the property for over 5 years but always put both CH and HW on for heating - just thought that was what I had to do and from your posts it looks that way as question 1 I do not have controls on the HW cylinder and question 2 I do see any of those motorised valves anywhere.
Its quite hard to see if there are 3 pipes into the boiler.

Would you have any approximate costs that a plumber may charge for the two options I have - I may just stay as I am as it all works fine but nice to keep costs down.

Thanks very all you advice.

When you select HW only, does the pump run?