Heating query

Ticked

In common with many in NI, we have oil heating but this may apply whatever the fuel. The circulation pump has several settings, presumably to adjust the flow to match the number of radiators in the system. I know that if the flow speed is too high (I think above 3 feet per second) it causes noise in the radiators, but what is the optimum flow speed? If it is low then there should be a more efficient heat transfer in the boiler but possibly less efficiency at the radiators as the water will be cooler before it leaves the radiator. Too high a speed and the opposite occurs. Or does it? If there is an optimum flow speed it could be a fuel saver but how on earth could it be measured?
Over to the brains for an answer, please feel free to say if I am talking complete shellfish!

RTNI

the pump will have 3 speed settings. What it it on now?

The general rule of thumb is that you set the pump as low as possible. Set the pump to the slowest speed (1) and see if you notice any difference in the heating of the house and the temperatures of the radiators all over. Turn the pump up to 2 if you find that the radiators are not hot enough or the house is noticeably cooler. If still cool, then set speed to 3.

Ticked

Cheers Robin, pump is at its lowest but I was never sure if that was the most efficient setting. Guess I'll go poke elsewhere for savings!

highrisklowreturn

For some reason my pump doesn't work on 3 - it only pumps at 2 max. Anything over this shuts it down, tho I want it to pump faster as radiators, in a coal system, never come out as warm as the domestic hot water.

GlynD

We have a combined coal and oil system. Our pump is set at 1. No matter what house I've ever owned or rented with a wet radiator system the pump has always been set at 1 and various engineers have told me that's how it should always be.

highrisklowreturn wrote: »

For some reason my pump doesn't work on 3 - it only pumps at 2 max. Anything over this shuts it down, tho I want it to pump faster as radiators, in a coal system, never come out as warm as the domestic hot water.

I don't know why your pump shuts down at 3 but you should get optimum heating at 1. No matter what the temperature of the water you're not going to increase it by setting your pump higher. Do you clean behind and between the panels of your high output back boiler? We find that just a week's burning will leave enough deposits to diminish the heating capacity of the boiler.

highrisklowreturn

The only part which can be cleaned is behind the back boiler, and no I don't do this except when deashing or sweeping. It is a wraparound back boiler built into a closed appliance so the other parts don't exist on mine.

I understand the pump won't increase the temperature - however a faster pumped speed around the system would prevent the water cooling as quickly before it reaches the radiators and returns to boiler. Unfortunately mine is even more confusing in that the farthest radiator in the system warms up quite well - in fact the best of all downstairs ones - yet the two living room ones just get above lukewarm. But as I say the DHW is roasting.

GlynD

highrisklowreturn wrote: »

The only part which can be cleaned is behind the back boiler, and no I don't do this except when deashing or sweeping. It is a wraparound back boiler built into a closed appliance so the other parts don't exist on mine.

I understand the pump won't increase the temperature - however a faster pumped speed around the system would prevent the water cooling as quickly before it reaches the radiators and returns to boiler. Unfortunately mine is even more confusing in that the farthest radiator in the system warms up quite well - in fact the best of all downstairs ones - yet the two living room ones just get above lukewarm. But as I say the DHW is roasting.

I think you're overestimating both the speed at which hot water travels around the system and how fast it cools.

You need a good plumber to balance the system I would say because the mysteries of valves etc are beyond the ken of most of us.

highrisklowreturn

I don't think it's balancing - as I say the farthest radiator from the boiler is the warmest on the ground floor, which wouldn't be the case in an unbalanced system. Also I've semi balanced it myself in that the two top rads have their valves closed 4/5 of the way yet still heat. And again there's no rad in the system gets as warm in the water. I think it's possible down to two things - the first being that the pipes are both on the left side of the fire ie it doesn't flow through the boiler to the return, and that some of the piping is 10mm and this can cause constrictions.

highrisklowreturn

Another thing I read is that the trvs on the rads don't like solid fuel and aren't compatible with it - not sure why this would be.

GlynD

highrisklowreturn wrote: »

I don't think it's balancing - as I say the farthest radiator from the boiler is the warmest on the ground floor, which wouldn't be the case in an unbalanced system. Also I've semi balanced it myself in that the two top rads have their valves closed 4/5 of the way yet still heat. And again there's no rad in the system gets as warm in the water. I think it's possible down to two things - the first being that the pipes are both on the left side of the fire ie it doesn't flow through the boiler to the return, and that some of the piping is 10mm and this can cause constrictions.

It's normal to find that one of the radiators is designated as a "heat loss" or "heat leak" radiator with a SF system. This is the one which will heat up first and cool down last. It's a safety valve really. It gives the heat from the back boiler somewhere to go to stop it exploding.

highrisklowreturn

Yip, this is the radiator in the bathroom in my case.