Boiler question.... re: Flame and Pump

Mr_Ted

becksfaz wrote: »

I'm not sure when the system was last serviced - we are tennants that moved in to this house in Aug.
My problem is that I thought on boilers when the water temp was hot the flame goes out (so you stop using gas) and the pump continues to push the water around to the rads. With this boiler, the flame is on all of the time so always using gas. Pump never functions independantly.

You should have a copy left in the property of the Landlords Gas Safety Certificate which is required by law annually, although this does not mean the appliance was serviced!

You have you say proved that the room stat works so therefore the house or more particularly the position in which the room stat is fitted is never reaching the temperature it is set at!

From what you say about radiators being red hot with the TRV's OFF it is possible the TRV's are fitted incorrectly in which case balancing the system will have little effect!
There is a theory, which is incorrect, these days that a modern TRV can be fitted on either side of the radiator.
This is not so, the TRV needs to be fitted on the flow side (the side the heat enters the radiator) of the radiator, but modern TRV's can be fitted either way up which I think is where the misinformation occurs.
The reason a TRV has to be fitted on the flow side of the radiator is so that balancing can be correctly carried out on the lockshield (outlet valve) without affecting the heat output of the radiator whilst creating a balanced feed to all the radiators!

bengasman

Mr_Ted wrote: »

...There is a theory, which is incorrect, these days that a modern TRV can be fitted on either side of the radiator...

That is not a theory, but manufacturers' specification.

Mr_Ted wrote: »

The reason a TRV has to be fitted on the flow side of the radiator is so that balancing can be correctly carried out on the lockshield (outlet valve) without affecting the heat output of the radiator....

Total nonsense. A biflow trv can be fitted on flow or return side, as can the lockshield. The lockshield will regulate the flow through the rad, AND the heat output. Stating that balancing does not influence the output, shows a fundamental lack of understanding.

Although a proper balance is important for the correct working of the system, it is unlikely to influence the amount of time that the boiler is lit.

ariba10

You are not confusing the Pilot light with the burner flames are you?

bengasman

jalexa wrote: »

... I prefer a simple "rule of thumb", a hot large radiator = 3kW, and a hot small radiator = 2kW....

There is a much more accurate way of determining the output of the rads.
Add up the width of each radiator-PANEL ( in other words twice the width for a double rad ). The total length in meters is the radiator output in kW if the rads are 600 mm high.
This is about as accurate as you can get, as contrary to common believe, radiators do not have a set output; you have to allow for about 20% error margin on the value given by the manufacturer.

bengasman

jalexa wrote: »

...if you are (reasonably) happy with a room temperature and the radiator without a TRV is still "hot" screw down the lockshield valve by half a turn."

This is really bad advice. The lockshield valve is for balancing the system, not for controlling the temperature. You should only interfere with them if you know what you are doing and have the necessary equipment to carry out balancing correctly. No offense to the op, but he is unlikely to have either.

becksfaz

ariba10 wrote: »

You are not confusing the Pilot light with the burner flames are you?

No its def the flame light

becksfaz

bengasman wrote: »

This is really bad advice. The lockshield valve is for balancing the system, not for controlling the temperature. You should only interfere with them if you know what you are doing and have the necessary equipment to carry out balancing correctly. No offense to the op, but he is unlikely to have either.

You're right, I wouldn't know what I was doing (though the 'he' is actually a 'she').
The landlord came and sorted the balancing but as I've not noticed any difference, so Im still convinced it's a boiler and/or stat issue. Think it's time to call in a professional....

bengasman

becksfaz wrote: »

...The landlord came and sorted the balancing

In all likelihood, he fiddled with the balancing, but didn't come even close to "sorting it".

becksfaz wrote: »

but as I've not noticed any difference, so Im still convinced it's a boiler and/or stat issue. ....

It's neither, it isn't an issue at all. If the boiler was electronically range rated down to minimum, and you have more than 10 metres of radiator panel in total, they simply dissipate whatever the boiler produces in heat. Perfectly normal, and no reason for concern in terms of gas waste.

Simple test will prove this. Turn all radiators of bar the one where the roomstat is, and you will see the boiler starting to "cycle" (coming on, going off alternately).
If you want to save gas, turn down trv's one click at a time until the rooms are consistently too cold. Then turn them back up half a click.
You are probably acclimatised to a "too high" temperature, so it will pay to walk around for a few days wearing a jumper in stead of bikini.

becksfaz

bengasman wrote: »

You are probably acclimatised to a "too high" temperature, so it will pay to walk around for a few days wearing a jumper in stead of bikini.

What a judgemental comment to make.... and an unjust one at that. Thought the purpose of this site/forum was to offer help/advice, not dish out sarcastic jibes! My OP was a simple question about boilers, this remark is irrelevant to what I asked.

HappyMJ

becksfaz wrote: »

House has wall and loft insulation so wouldn't think it would be insulation. yes stat is in the hall so lack of control will contribute. Landlord sent someone out last week to balance the system but not noticed any difference (?)
I'm getting some paper room thermometers today from my step dad and putting one in each room so see if I can lower hall stat, but going back to the TRVs - we don't have them on all the rads. Got them on the 2 rads in the lounge, downstairs toilet, 1 hall rad downstairs, our room and our ensuite (rad off in ensuite though). No TRVs in kitchen, playroom, kids bedrooms, office, 1 downstairs hall rad and upstairs hall rad.

You have 14 radiators....That's a huge house. No wonder the bill is big. I would expect it to be big. The example that everyone compares to is 16,500kWh per year for the "average" home. The average home could be considered a 3 bedroomed semi detached house. A radiator in each bedroom, lounge, bathroom, only one in the hall, maybe dining room, maybe the downstairs toilet, maybe the kitchen. That's 6-9 radiators. Half the system that you have. You could quite easily expect your bills to be twice the national average. You also need to add a bit as your boiler is not the most efficient and up to date. It's about 72% efficient. Only about 5 years ago the national average was 20,500kWh per year based on the average installed boiler being as efficient or slightly less efficient than yours at 65%. The average was recently reduced due to boilers becoming more efficient. They are now 90% efficient. Double that is 41,000kWh per year.