Will cylinder thermostat setting effect rad temp?

[zigg]

We have a 'W' plan heating system (hot water priority), and I was wondering if the cylinder thermostat setting has any effect on the radiator temps. At the moment, the hot water is very hot indeed, practically scalding. But the radiators very rarely get what I'd call 'hot', just very warm.
Would the hot setting for the hot water be causing the 3 way valve to send a bigger flow to the cylinder, and therefore not much to the radiators?
Thanks for any help.

 

[oilhead]

On a W plan, you get no heat to the rads until the cylinder is satisfied. Yurn your cylinder down to a lower temperature.

 

[Whitespirit66]

The cylinder stat shouldn't have any affect on rad temps. Just acts on the hw.

With the heating only on, does the pipe from the diverter valve to the hw cylinder get hot?

Is the cyl stat properly located and making good contact with side of hw cyl?

 

[zigg]

@Whitespirit66, being a 'W' plan system, I cant select just heating, it's either, hot water, or hot water and heating.

@oilhead, is the diverter valve infinitely variable, or does it only have 2 positions, hot water, or hot water and heating? What I mean is, if the cylinder is calling for hot water, will the valve say, move to a position whereby most hot water is going to the cylinder, and only a trickle to the rads, or will it shut off feed to the rads completely until the cylinder has reached temp, and then open to allow rads AND cylinder a supply of hot water?

Thanks both, for your speedy replies.

 

[gas112]

Are yous sure cylinder stat wont affect rads ,, never heard of heat store ?

 

[Whitespirit66]

@Whitespirit66, being a 'W' plan system, I cant select just heating, it's either, hot water, or hot water and heating.

@oilhead, is the diverter valve infinitely variable, or does it only have 2 positions, hot water, or hot water and heating? What I mean is, if the cylinder is calling for hot water, will the valve say, move to a position whereby most hot water is going to the cylinder, and only a trickle to the rads, or will it shut off feed to the rads completely until the cylinder has reached temp, and then open to allow rads AND cylinder a supply of hot water?

Thanks both, for your speedy replies.

Have you got a 3 port valve. What model number is it?

W Plan explained -

http://www.google.co.uk/url?sa=t&rc...t_IafbQkXlvpx2h7g&sig2=531tDK_Myn9foi_Xqxpjuw

 

[zigg]

I have got a 3 port valve, but it's wired in to behave as a 2 port, 'cos I only have a controller for a w plan.
Actually, it's a 3 position valve, not a 3 port, so it's wired to be a 2 position valve. Which, in reality, means it never shuts off the hot water feed.

 

[picasso]

Your valve has been wired wrongly if that whats happening, the white and grey wires of the valve should have been joined together and the default of the valve would be hot water port open, when the cylinder stat is satisfied the grey/white would be energised closing the hot water port and opening the central heating, get your wiring checked.

 

[oilhead]

The W plan valve (if Honeywell; V4044c) only has 3 wires. When the cylinder stat is satisfied, the valve opens to the heating port. It follows therefore, that the higher the cylinder stat is set, the longer it will take to change to heating. It does not give a mid position and you only have a brown and a blue wire plus earth.

 

[zigg]

Thanks guys. Will check wiring tomorrow

 

[zigg]

Well, wiring seems in order. I increased pump speed to 2 while I had access to the airing cupboard (dont ask) and backed off the cylinder stat a tad. Rads seem a bit hotter but not much. More noise from pump too! Today, I turned all rads off except the last one downstairs( only 2 downstairs, totally inadequate I know, but thats not why I'm here) and within minutes it was too hot to touch. But as soon as I start to crack open other rads, the temp drops sharply! Ive sort of reached a happy compromise with all the rads, but I'm not happy. Surely all the rads should be able to get HOT, and not just warm? Room stat is maxed out. It always has to be, it was never possible to overheat the house ( I wish).
I powerflushed the system about 3 yrs ago, and got all the crud out, but still never managed to get every rad HOT.
I know there's air getting in from somewhere, but have never managed to trace where. When the pump kicks in, theres a long whooooosh as air is pulled in, then it settles down for a bit. Funny thing is, I hardly ever need to bleed a rad, maybe once or twice a year.
When I powerflushed the system, I could see air coming through on the normal direction, but not on the reverse direction......odd.
I drew some water from a rad just now, and it was crystal clear.
I'm at a loss as to what's preventing my rads from getting HOT.

 

[Blagard]

I have got a 3 port valve, but it's wired in to behave as a 2 port, 'cos I only have a controller for a w plan.
Actually, it's a 3 position valve, not a 3 port, so it's wired to be a 2 position valve. Which, in reality, means it never shuts off the hot water feed.

Aside of this being a poor setup by not making full use of the valve. The hot water circuit may be fully open acting like a bypass. There really ought to be a gate valve or L/S Valve on the hot water primaries to regulate the flow like balancing a radiator.

 

[zigg]

Aside of this being a poor setup by not making full use of the valve. The hot water circuit may be fully open acting like a bypass. There really ought to be a gate valve or L/S Valve on the hot water primaries to regulate the flow like balancing a radiator.

Now you mention it, there is a gate valve, just after the diverter valve outlet to the DHW coil, and as far as I remember, it's fully open. Could that be why my rads aren't getting fully hot?

 

[zigg]

I didn't mean that my diverter valve WAS acting as I described, but that I thought that was how it behaved as a 2 position valve. It seems that I am wrong in that assumption, and that, in fact, when the HW is satisfied, and heating is called, that the valve moves to shut off feed to the HW circuit.Sorry if I misled anyone.

Would a malfunctioning room stat cause the problems I described?

 

[lauriehurman]

Zigg
Listen to Oilhead. He got it right first time.
If your 3-port valve has switched live/neutal/earth then it's a diverter and you need W plan wiring.
If it has 3 switched live/neutral/earth then it's a mid-position and you need to change to "Y" plan wiring.

Laurie