cylinder stat temp

[Notebook64]

Hi
What temp should this be set at?

Reason for question is that my myson apollo pump works ok on high, but switch the high low switch to low and it runs all the time, even if the boiler hasnt fired up.

I think it is currently set at 60.

someone said that the low on the high low switch is lower that this - could this cause the pump to run all the time?

Thanks

 

[D_Hailsham]

What temp should this be set at? I think it is currently set at 60.

That's the correct temperature

Someone said that the low on the high low switch is lower that this - could this cause the pump to run all the time?

They are wrong. The Low setting gives a temperature of about 65C. The idea being that you use the High setting (82C) in the winter and the Low setting in the summer, when all you need is hot water.

Reason for question is that my myson apollo pump works ok on high, but switch the high low switch to low and it runs all the time, even if the boiler hasn't fired up.

The overrun thermostat has probably failed.

 

[Notebook64]

What temp should this be set at? I think it is currently set at 60.

That's the correct temperature

Someone said that the low on the high low switch is lower that this - could this cause the pump to run all the time?

They are wrong. The Low setting gives a temperature of about 65C. The idea being that you use the High setting (82C) in the winter and the Low setting in the summer, when all you need is hot water.

Reason for question is that my myson apollo pump works ok on high, but switch the high low switch to low and it runs all the time, even if the boiler hasn't fired up.

The overrun thermostat has probably failed.

Have replaced this - are there any other things that might cause this?

 

[D_Hailsham]

The overrun thermostat has probably failed.

Have replaced this - are there any other things that might cause this?

Which model Apollo do you have? The data is on the back of the outer cover. GC number is best - it starts with 41.

Is the noise from inside the boiler? Are you sure it is the pump you can hear? Where is the pump located?

Have you connected the overrun stat correctly? Red = Terminal 1, Yellow = Terminal 2, Brown = Terminal 3.

The Hi and Lo stats do not affect the pump.

 

[Notebook64]

The overrun thermostat has probably failed.

Have replaced this - are there any other things that might cause this?

Which model Apollo do you have? The data is on the back of the outer cover. GC number is best - it starts with 41.

Is the noise from inside the boiler? Are you sure it is the pump you can hear? Where is the pump located?

Have you connected the overrun stat correctly? Red = Terminal 1, Yellow = Terminal 2, Brown = Terminal 3.

The Hi and Lo stats do not affect the pump.

Hi and thanks
the number - 41 789 53 15/30b
pump next to boiler

long story -
zone valve not shutting off every now and then
changed and as above junction box / pump - water ran down onto this.
turned electric on and tripping
isolated the pump - all ok
changed pump - winding smell
all ok - zone etc working fine - indeed all ok.
On high everything working fine.

On low - using it some time later - as thought all was ok - heared the pump running - touched it - hot and feel the vibration off it.
This was continually running.

If i turned the cylinder stat down then the pump would stop - turn it up and it would kick in again.

Sorry for sounding dumb, but is the high low only used on hot water, or only on central heating.

Off fo an interview soon so no time to look at the wiring, sure I have checked this previously. Will check later

just read your post - hi low is for hot water only? what controls rad water temp? - confused?

Thanks

 

[D_Hailsham]

Sorry for sounding dumb, but is the high low only used on hot water, or only on central heating.

just read your post - hi low is for hot water only? what controls rad water temp? - confused?

To answer the easy question first.

You set the switch to LO in the summer, when all you need is hot water. You set it to HI in the winter, when you have the central heating on. If you leave it on LO in the winter the rads will probably not get hot enough to warm the house. You should have a thermostat on the wall of the house to control the room temperature.

zone valve not shutting off every now and then.
changed and as above junction box / pump - water ran down onto this.
turned electric on and tripping
isolated the pump - all ok
changed pump - winding smell
all ok - zone etc working fine - indeed all ok.

So water was getting dripping on to the junction box, which damaged the pump and the zone valve? Both replaced. How many motorized valves do you have and what type, two port or three port?

If I turned the cylinder stat down then the pump would stop - turn it up and it would kick in again.

You said earlier that it did this without the boiler coming on. That's weird as the output from the cylinder stat should turn the boiler on.

 

[Notebook64]

Sorry for sounding dumb, but is the high low only used on hot water, or only on central heating.

just read your post - hi low is for hot water only? what controls rad water temp? - confused?

To answer the easy question first.

You set the switch to LO in the summer, when all you need is hot water. You set it to HI in the winter, when you have the central heating on. If you leave it on LO in the winter the rads will probably not get hot enough to warm the house. You should have a thermostat on the wall of the house to control the room temperature.

zone valve not shutting off every now and then.
changed and as above junction box / pump - water ran down onto this.
turned electric on and tripping
isolated the pump - all ok
changed pump - winding smell
all ok - zone etc working fine - indeed all ok.

So water was getting dripping on to the junction box, which damaged the pump and the zone valve? Both replaced. How many motorized valves do you have and what type, two port or three port?

If I turned the cylinder stat down then the pump would stop - turn it up and it would kick in again.

You said earlier that it did this without the boiler coming on. That's weird as the output from the cylinder stat should turn the boiler on.

Again thanks

thermostat on wall - yes

used to put it on low if heating required in summer evening.

still lost - I thought that the cylinder stat would supply 60 degree water due to stat on tank in hot water only mode irrespective of the high / low switch? is that correct?

replaced zone valve as not working all the time - when doing this water got on the junction box and blew the pump.
1 zone valve - might be using wrong terminology here - what I mean is on hot water only the rads would get warm - mess with the slider on the valve and it would clear. use central heating and then go back to water only and they might get warm again as if passing - this is why I changed it - this has sorted it.
this has a b and down to the pump.


cheers

 

[D_Hailsham]

Just a bit of advice, before the Mods wake up. The "Quote" button should only be used when you actually want to quote all or part of a post. If you don't want to quote, you should use the "postreply" button, which is on each page, at the top and bottom of the topic.

thermostat on wall - yes

Good; I thought you did not have one.

used to put it on low if heating required in summer evening.

I assume "it" means the boiler stat. If so, that is OK as the rads will not need to get so hot in the summer.

I thought that the cylinder stat would supply 60 degree water due to stat on tank in hot water only mode irrespective of the high / low switch? is that correct?

Yes the cylinder stat controls the temperature of the water in the cylinder irrespective of the boiler stat setting. I suspect that the HI/LO switch pre-dates cylinder thermostats, so the only way of controlling the water temperature in the summer was to have the boiler temperature lower. If you have the stat set to HI in the summer, it will heat the water up quicker.

1 zone valve - might be using wrong terminology here - what I mean is on hot water only the rads would get warm - mess with the slider on the valve and it would clear. use central heating and then go back to water only and they might get warm again as if passing - this is why I changed it - this has sorted it. this has a b and down to the pump.

The valve looks like this? If so, its called a mid-position valve, not a zone valve.

View media item 5946
Water comes in "up" the T (port AB) from the pump and out of the sides to either the radiators (port A) or the HW cylinder (port B). The valve can take up three positions: Port A open; Port B open; and both Ports A and B open. When the valve has no power applied, Port B (hot water) is open as the valve is held in this position by a spring.

I am beginning to suspect a wiring fault as turning the cylinder stat up should light the boiler and turn the pump on. Is the pump wired directly to the boiler or to the junction box?

 

[Notebook64]

Hi
the picture is correct for the a-b jobby
the pump wires run to the junction box
I checked the wiring with my neighbours and it checked out the same - however lots of the same colours - neutrals I guess. This was a year or two so cant quite remember when this started. Just changed the thermocouple on the pilot and this got me thinking again.

the cylider stat up down - I woke and the pump was running for ages - turn it down and the pump off back up and the pump on - would only bring in the pump if I remember and not fire up the boiler - again from memory.

I think i remember the pump running like this one night when the pilot light had gone out?

 

[D_Hailsham]

the pump wires run to the junction box

Is that the junction box where everything (thermostats, valves etc) are connected?
Is it the type with 10 pairs of terminals in a line?
Which terminal is the pump Live connected to?
Which terminal is the orange wire from the valve connected to?

I checked the wiring with my neighbours and it checked out the same - however lots of the same colours - neutrals I guess.

There is no standard colour scheme for wiring heating systems! Blues and green/yellows are sometimes used to carry voltage.

Just changed the thermocouple on the pilot and this got me thinking again.

If the pilot was out, the boiler would not light. But that would happen with the switch in both HI and LO positions.

Does the problem happen only when Hot Water is ON and the switch in LO?

Please test all combinations of Heating, Hot Water and HI/LO switch (there are six: CH - HI; CH - LO; HW - HI; HW - LO; CH +HW - HI; CH + HW - LO) and report results.

 

[Notebook64]

Hi
I have been running it on high and working perfectly well for a year or so. The reason I changed the thermocouple this week was exactly that - the pilot light wouldnt light, nothing to do with the original fault and this fixed the pilot light and operation of the gas valve I guess.

Off away for a few days, but if ok will check out and comment back or pm you. Thanks Again
Nick

 

[picasso]

I havent got the correct instructions for this boiler but the ones I do have say that if a programmer isint fitted then the link between hot water and ON must be removed, so its a bit of a shot in the dark but the installer may have the link in place.