Boiler stove nightmare

Scoobnut

So it's 24 hours since I shut down the 2 biggest raidiators and the others have got hotter. I have never heard the pump switch on so much, even my son says his room is no longer a freezer. Unfortunately, we have gales again (the norm here in the winter) which has caused the stove to drop in heat, struggle to regain it and have a nice cold wind blowing through the bottom vent so I'm force to shut it down or waste fuel.

The chimney liner is 18 months old and was cleaned in the summer. My husband as been on the roof and checked the chimney and says its fine, we can't check from the stove side as it fixed through the wall into the chimney. I'm still thinking of getting a Rotorvent Ultralite 2 as it's supoosed to help in high winds and aid draw.

I worked out (roughly) that we should have got a 25kw stove. 19 to boiler and 6 to room. My husband has agreed to get quotes for flushing and balancing but it does depend on cost. I showed him some YouTube videos but as a retired joiner he's unwilling to attempt it himself.

suki1964

You need to weigh the cost of getting the job done against cost in savings on the heating over time. If only half the rad is getting hot, there's no point really in throwing coal on the stove at the rate of knots, the rooms are never going to get toasty

It really does sound like the stove just isn't powerful enough to feed those rads, I have a 5kw stove just for one room - ok its a big room and open plan with the hall stairs opening off it - and that keeps that room at a constant 24oC and takes the chill of the bedroom enough that I have no rad on in there

I have a weird layout. My stove is actually on my upstairs landing which is ginormous , we use it as a living room and have four rooms leading off it. No hallway because it is actually the landing So two bedrooms are directly off it. The only rad that is on upstairs is the bathroom one

We did have another stove downstairs but thats been removed because mums not fit to use it now. That was 4kw. 9kw joint and we still had to have the oil running twice a day to heat the rest of the house and the hot water

Im on the NE coast of Ireland so we have the same weather. Right now theres a solid frost outside still. We do have oil thankfully but we also need an electric rad in mums bedroom on a thermostat for nights as she feels the cold so much. Heating bills are horrendous so it really is beneficial to get what you have got working as efficiently as possible

matelodave

Scoobnut wrote: »

So it's 24 hours since I shut down the 2 biggest raidiators and the others have got hotter. I have never heard the pump switch on so much, even my son says his room is no longer a freezer. Unfortunately, we have gales again (the norm here in the winter) which has caused the stove to drop in heat, struggle to regain it and have a nice cold wind blowing through the bottom vent so I'm force to shut it down or waste fuel.

The chimney liner is 18 months old and was cleaned in the summer. My husband as been on the roof and checked the chimney and says its fine, we can't check from the stove side as it fixed through the wall into the chimney. I'm still thinking of getting a Rotorvent Ultralite 2 as it's supoosed to help in high winds and aid draw.

I worked out (roughly) that we should have got a 25kw stove. 19 to boiler and 6 to room. My husband has agreed to get quotes for flushing and balancing but it does depend on cost. I showed him some YouTube videos but as a retired joiner he's unwilling to attempt it himself.

TBH you should really work out how much heat each room requires (plenty of calculators on t'interweb) to decide what sized rad you need in each room rather than just fitting rads and hoping that they are big enough or just bunging in a boiler with a similar philosophy.

Have your rads got TRV's - they would help limit the amount of heat that gets dissipated in each room as they'd close down when the room was warm enough and allow the heat to get to other rooms. It's easy to limit the amount of heat a big rad gives out by turning it down but you cant easily get more heat out of a radiator that's too small

However do ensure that at least one rad (the one in the room with the thermostat) is NOT fitted with a TRV as you need to allow excess heat from the boiler to dissipate.

Make sure that your room thermostat isn't in the same room as the boiler as it wont operate correctly and will shut down the pump when the room with the boiler gets up to temp rather than when the house does

Scoobnut

The heating was in when we bought the house with all rads were running of a Rayburn. Sadly the Rayburn was beyond repair and we got the stove to replace it. My husband insisted on getting the one we have as it was the cheapest and he said it would be fine. All the raidiators are big, the living and our bedroom are the biggest. I would like to change them as they are decades old and I know that the one in my sons room is far to big but he's not keen on it. Each raidiator has a thermostat except the hall which is the leak raidiator. There is no room thermostat.

matelodave

If there's no room thermostat what controls the pump - is it just on all the time or has the boiler got a stat to control it.

As I said you can turn the rads down a bit and balance the system to ensure that just one or two rads don't dissipate all the heat. We had a problem rad which never got hot until we balanced the system and sorted out the TRV's. You could check that they are all working an set correctly

Scoobnut

We have a pump that's connected to the pipes behind a panel in the bathroom. It comes on when it hits 50c. The thermostats on the raidiators are old and poorly fitted.
I went online and calculated that we actually need 8.590. The 2 biggest ones are over 3 each and too big for the size of rooms. Replacing the raidiators is the only option.

matelodave

OK with that bit of info you can probably work out what is happening.

1 - with all the rads on the pump probably doesn't run very much because the cold return return water is taking a long time to get up to 50.

2 - With some of the rads turned off the return water will be a bit warmer so the boiler will get to 50 a bit quicker so the pump turns on and off more frequently

3 - you need to balance the system so the pump runs for a lot longer but you also need to keep feeding the fire to keep the temperature up. In the end if you are extracting all the heat from the boiler so it doesn't get up to 50 degrees the pump wont run at all or only for a very short bursts until the cooler water drops it below 50.

You might get a better result by just cracking open the radiator valves to keep the pump running - although the rads wont get red hot they should all stay warm for a lot longer. In the end a continuous gentle all round warmth will be better than a red hot blast once every few minutes when the pump kicks in.

I'm afraid it's going to be a bit of trial and error before you get it right but expect to be showing in at least 3kg of fuel an hour to keep the temperature up. A bigger stove would just use more fuel so see if you can tune your existing system to work a bit better.

Scoobnut

That makes a lot of sense. I have looked up balancing and yes it looks very faffy but not impossible, somthing I will try. I have noticed the pump switches off after 2 to 3 mins and the return pipe gets hotter quicker than the flow pipe.

With the livingroom and our bedroom raidiators shut down and the stove running at full throttle it has made a big difference although we have no wind today so it's burning a bit slower. The draft I feel through the bottom vent is normal my hubby says. It would be nice to get the stove to run overnight when really cold but as it never ran the heating It was a waste of fuel.

matelodave

The flow pipe should get hotter quicker than the return - think about it.

The boiler makes the water hot, the pump starts up and shoves the hot water out of the flow pipe, through the rads which should dissipate the heat so the return water should be cooler.

If it's too cold then the boiler will cool down and the pump will stop until it gets hot enough to turn the pump back on and so the cycle continues.

You need to adjust the flow through the rads so that the return temperature is just above 50 degrees so the pump doesn't keep cycling. You also need to feed in enough fuel to maintain the water temperature above the 50 degree pump threshold if you want to heat the house as well as the room that the boiler is in. Can you divert heat towards the boiler tubes in preference to the room heater.

However if the pump is not running then the water should get very hot very quickly and can only move away from the boiler in both directions due to expansion or thermo-syphon effects.

Scoobnut

"The flow pipe should get hotter quicker than the return" looks like I had it the wrong way round. Think the fitter said anything to stop me asking questions. Anyway, the bottom pipe is always hot so must be the flow and the top is the return.

"Can you divert heat towards the boiler tubes in preference to the room heater"? Don't think I can do that. The heating system is very old, at least 18 years. The stove is the only new part of it.