Boiler control

[botg6969]

Hello,

I have a very old Olympic Thorn boiler (38/50 model I think), that's still going strong on a gravity HW / pumped CH system.

It currently has very basic controls on the boiler itself:

a thermostat
a switch for once a day / constant / twice a day
a switch for HW / off / CH & HW
a mechanical timer with two sets of tappets

It's a very basic system, there's no valves, or other thermostats anywhere.

My understanding is that the only difference between HW and CH & HW is that with HW only, the pump is not turned on. (please can you confirm if I am correct?)

I've fitted HouseHeat RF TRVs to most of the radiators in the house so that each rooms temperature can be locally controlled by the RF Thermostat in the room (I've left the downstairs toilet and upstairs bathroom TRV-less currently).

I now have an accompanying HouseHeat product that listens to what the RF Thermostats are doing and can "control" the boiler and / or pump so as to prevent wasted energy if there is no demand for heat from the RF Thermostats. In my system, I presume that I should connect this to the pump only, as otherwise it would switch the boiler off completely and therefore the HW too?

I'd also like to replace the old mechanical time switch with a modern digital one to give more control over on/off timing through the week. Can you recommend a replacement that would work with this boiler? I presume I need one that can give the correct outputs to work with the once a day / twice a day setting on the boiler?

I've asked a couple of plumbers to quote for doing the above for me and have been told by one that it's not possible to change the timer switch and by the other that the system is too old and would need converting to fully pumped?!?!

I'd apreciate some honest advice, as I'm reasonably competent at doing this sort of work myself. Failing that, anybody covering Northants that wants to give me a quote?

Ta,

Martyn

 

[Agile]

You would need a relay so that your control powers the boiler and the pump when its activated.

Any timer or programmer will replace the simple timer you have.

But you really are approaching this from the wrong angle! You have an old inefficient boiler without even a pumped HW side.

It reminds me of this customer I have who called someone else to repair her boiler nine months ago who charged £200 for something I would have doine for £112 !

She has virtually NO loft insulation and 12m of UNLAGED 22 mm heating pipes in her loft.

Yet she is having a solar hot water system fitted at a cost of about £4000 while I could have fitted it for about £3000. That will have no payback whereas insulating th loft and pipes there will save the cost inless than two years!

She asked me to quote for a new boiler because she had spent £600 on the boiler recently. On analysis she spent this £200 on the boiler and I replaced one motor valve about a year ago and repaired another last week for £168 and £128 respectively.

Tony

 

[botg6969]

Thanks for the reply Tony.

If I connect the control to both the boiler and the pump, will that not also switch off the HW too though?

For the programmer, do I need anything special to take into account the difference between the once a day and twice a day setting on the boiler?

I appreciate that the boiler is old and inneficient but based on the fact that it is still working fine I can't justify the expense and disruption of replacing it.

Over the years I have had various quotes to replace it but because of the design of the house (chipboard flooring) the cost and disruption to do this is a lot!! Nobody is willing to just replace the boiler without ripping out everything else too.

So I'm doing my best to improve what I have.....


Martyn

 

[kevplumb]

Can you recommend a replacement that would work with this boiler? I presume I need one that can give the correct outputs to work with the once a day / twice a day setting on the boiler?

just about any will work with this boiler its down to what you want and how much you want to spend

 

[Agile]

DELETED following Kevplumbs next posting.

Tony

 

[kevplumb]

You will have to use a double pole relay to avoid connecting the boiler and the pump together during hot water heating.

A simple way without soldering is a 230v ac octal base relay with a socker base with screw connections. Maplins I expect.

It sounds as if your boiler replacement quotes have all been for combi boilers. For a heat only there should not be much need to take up floors.

Tony

what a load of utter and total b olloc ks

 

[Agile]

As Kevplumb has been so disrespectful about my advice to you, I have deleted it and will not be giving you any further help.

I am sorry about this.

Presumably he will give you the advice you need shortly!

Tony