Back boiler not heating rads

Mharan

Registered User
Messages
14
When I put on a fire on the stove which has a back boiler I have no hot water and my rads are barely heating. My oil heating works fine with heat and hot water. Stove is supposed to be able heat 13 rads. Can anyone give me some advice. Thank you
 

Palerider

Frequent Poster
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1,480
Is the hot water pipe exiting the stove hot and the return going in ( the bottom pipe ) cold, if so you should be heating your water cylinder through convection and it is either a circulating issue or a thermostat issue, assuming you have a decent fire going.

It takes my stove about 75 minutes after lighting a good fire for the circulating pump to kick in,.
 

Palerider

Frequent Poster
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1,480
I would not run a hot fire until you get that circulating pump fixed, the return pipe when it's hot is showing that the full system including your tank is hot, heat needs to escape from the stove that is where the pump comes in, look for it in your hot press, maybe it needs switching on as mine does, look for that switch ( like a light switch on the wall ), maybe you have a thermostat and it is set too high, if so switch it down to 60 degrees, if you have this it will be in your hot press, it could also be faulty, not an expensive fix either.

If you can find the pump and it is switched on then you will hear it working, if it is silent get a plumber, a heat merchants circulating pump cost me €51 when I needed one recently, let the plumber know that you expect the pump to be around €60, get to it asap and keep a small fire on in the interim.
 

Mharan

Registered User
Messages
14
I have had this problem since we put in the stove 7 yrs ago. A plumber did put 2 thermostat in one upstairs and one downstairs. Should they both be on or one on one off but again it doesn't seem to change anything
 

Palerider

Frequent Poster
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1,480
They sound like room thermostats rather than a thermostat on one of your pipes from the stove to the hot press, trace these pipes, it won't be difficult and see if a thermostat is on one, if not you need a plumber.
 

Mharan

Registered User
Messages
14
They don't seem to work as if I turn off downstairs one the rads still get lukewarm and if I turn on upstairs one it still doesn't heat up. There is only one thermostat in the hot press.
 

Palerider

Frequent Poster
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1,480
Ok, great, you might have air in the system, bleed each radiator until the water runs freely from the bleed valve, that said they should be fine if they get hot when the oil is used for heating.

If that fails you need a plumber as you have a blockage somewhere maybe in a non return valve.
 

Mharan

Registered User
Messages
14
Have bled rads and I think they are beginning to heat up. I will let ye know in about 30 mins
 

Mharan

Registered User
Messages
14
I have turned off 2of the bigger rads as I don't need them all on. The rest are heating up nicely. One other question does it matter if you turn pumps off over night, is there any need
 

Mharan

Registered User
Messages
14
So if I want hot water in the morning turn it off and if I want rads to stay warm leave it on?
 

Leper

Frequent Poster
Messages
1,008
Back boilers are well outdated. Even we replaced ours 25 years ago in favour of mains gas heating. I retired a year ago and had a new gas boiler installed with zones where we can have heat directed when necessary. Even our hot water needs are covered efficiently (no need to heat a full copper cyliner and we don't even have a copper cylinder now).

The good news:- We got a grant of about €1150 off the €4K bill.

I advise:- Get rid of that back boiler. It's relatively inefficient, unclean and now appears useless. Loans have never been cheaper.
 

Leper

Frequent Poster
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1,008
1. Just for the record. Back boilers need constant cleaning with elongated wire brush i.e. getting elbow deep in soot etc while using up all your energy scrubbing where you cannot see. This could be your problem. Only thing, if you haven't been cleaning the back boiler, it has probably seized up with deposits of coal extract which by now has probably solidified beyond hope.

2. If your upstairs radiators are being heated and the downstairs radiators cold it means:- Your water pump is out of order.

3. If your upstairs radiators are cold, your system needs cleaning at least. (a) Vent the radiators with the proper "key" and/or (b) Clean the livin' bejazus out of your back boiler with proper scraper and elongated wire brush. Throw out the wire brush afterwards as it will probably be useless for future use.
 
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