Heat not being disbursed evenly

[toxictoad]

hi,

I have noticed that my central heating doesn't seem to be disbursing heat evenly around my rads.

Here's a breakdown of the system,
- All rads are 60 cm high
- All upstairs rads are single convector
- Thermostat is at top of stairs in hall
- The living area is open plan
- All rads except the hall rad have built in thermostats

Sabre 25HE Condensing boiler (situated in Bedroom 1 / Back room)
90 cm rad (bedroom 1)
60 cm rad (bathroom / back room, directly behind boiler)
120 cm rad (bedroom 2 / boiler is directly behind boiler in bedrrom 1 / front)
60 cm rad (bedroom 3 / front)

140 cm single convector (downstairs hall / main controller rad)

60 cm double convector (living room / back area / downstairs)
120 cm double convector (living room / front window bay / downstairs)

All the rads downstairs are outputting the same amount of heat and are set to high on the individual thermostats

The bahroom rad is set to 1 and outputs the same heat as the downstairs rads that are set to 5 (max)

Bedroom 1 is outputting less than the bathroom and is set to 4
Bedroom 2 & 3 are also set to 4 but is outputting even less than bedroom 1.

I have checked the pessure on the boiler and I can't get it to go any higher.

Is there any reason for it doing this and why?

Thanks

 

[ChrisR]

outputting the same amount of heat

How do you know, what are you measuring?

Thermostatic rad valves set on max do absolutely nothing until the ROOM temperature gets very high, like 30º, depending on make.

Different makes of valves have different ranges, and a lot of them can be altered by twiddling things inside.

If the room temp is below the temp set on the trv, whether it's "1" or "6", the valve will be wide open. TRV's are for controlling, not adjusting, the radiator output.

The system should be BALANCED by adjusting the non- trv valves. See reference section

I have checked the pessure on the boiler and I can't get it to go any higher.

That sounds alarming. Do you know what you're doing? What IS the pressure?

 

[Nige F]

I am sure you know what you`re doing, good luck

 

[toxictoad]

Thanks guys

How do you know, what are you measuring?

The elbow test well not quite my elbow but I put my hand on each rad and it's very clear that some are hotter than others, hence more heat being outputted...

That sounds alarming. Do you know what you're doing? What IS the pressure?

Of course I know what I'm doing...
When I had the system installed, the (qualified) plumber showed me what to do if I lost pressure to the system (e.g. temporarily removed a rad for decorating)

There is a small lever that I hold in and turn and this raises the pressure, whola! The pressure is currently on two, max is four and it was just below two when they showed me.

I had another plumber come in and move one of the rads recently and he checked it all out after doing so and I haven't increased the pressure any further since then so I feel safe.

I guess it must be ok and it's my lack of understanding how the thermostats work / kick in because, over all, the upstairs is pretty warm and if all rads were outputting the same amount of heat as the bathroom rad it would be *very* hot up there. It just seemed odd that one rad that was set to one, was hotter than the other three that were set to four...

 

[chrishutt]

The pressure is currently on two, max is four

The maximum pressure is in fact 3 bar, since the PRV valve will open at this pressure and release any excess to outside. The normal setting for system pressure is around 1 bar, although it is normal for this to increase up to maybe 1.5 bar when the whole system is hot.

 

[toxictoad]

The pressure is currently on two, max is four

The maximum pressure is in fact 3 bar, since the PRV valve will open at this pressure and release any excess to outside. The normal setting for system pressure is around 1 bar, although it is normal for this to increase up to maybe 1.5 bar when the whole system is hot.

is that the same as the driving limit in the uk being 70 miles an hour but cars going 100 miles an hour? Sorry to be facetious... The meter dial does go up to 4 so I was just gauging it on this...

If what you're saying is right, and that the pressure is a *little* high, would I therefore need to bleed one of the rads to lower it?

 

[toxictoad]

ah.....I think that the pressure valve I mentioned is actually the valve that lets cold water back into the system so turning this (if I'm on the right tracks) would fill up all the tanks again (e.g. after one was removed) thus increasing the pressure...does that sound right?

Now the heating's been off for about 2 hours, the pressure has dropped to approx 1.75

 

[chrishutt]

......fill up all the tanks again (e.g. after one was removed)

You sound rather muddled about what is what in your heating system. If you read through the posts in the two sticky topics near the top of the topics list, you might at least be able to ask the right questions.

 

[Nige F]

The pressure is currently on two, max is four

The maximum pressure is in fact 3 bar, since the PRV valve will open at this pressure and release any excess to outside. The normal setting for system pressure is around 1 bar, although it is normal for this to increase up to maybe 1.5 bar when the whole system is hot.

is that the same as the driving limit in the uk being 70 miles an hour but cars going 100 miles an hour? Sorry to be facetious... The meter dial does go up to 4 so I was just gauging it on this...

If what you're saying is right, and that the pressure is a *little* high, would I therefore need to bleed one of the rads to lower it?

a better analagy would be removing the govenor on a diesel engine that limited it to 70mph.then driving it flat out on an Autobahn( no speed limit)