Alde comfort issue.

[MtB]

Just now, Rickent said:

Usually turn the boiler off when the water is hot enough for a shower but not exclusively so, swmbo has just washed the dishes with the boiler running, is this significant?

 

Yes. If you're using the hot water as the boiler runs, it probably never gets hot enough for the thermostat to shut it off. So we would not know for a fact that the thermostat ever worked. 

 

Just trying to build a picture of what's going on.

 

 

 

 

 

[Rickent]

2 minutes ago, Mike the Boilerman said:

 

Yes. If you're using the hot water as the boiler runs, it probably never gets hot enough for the thermostat to shut it off. So we would not know for a fact that the thermostat ever worked. 

 

Just trying to build a picture of what's going on.

 

 

 

 

 

Ok , no probs, maybe I should run it in the morning without the pump running and see if it overheats, if the thermostat works it should hold the water in the system at the right temp without overheating or am I missing something.

[MtB]

1 minute ago, Rickent said:

Ok , no probs, maybe I should run it in the morning without the pump running and see if it overheats, if the thermostat works it should hold the water in the system at the right temp without overheating or am I missing something.

 

Yes this was my next suggestion. Run it for the hour and take care not to use any hot water. Keep a close eye on the boiler to see if the main burners turn OFF at any point, then re-light, or if they just keep on going until the header tank boils....

 

 

 

[Rickent]

1 minute ago, Mike the Boilerman said:

 

Yes this was my next suggestion. Run it for the hour and take care not to use any hot water. Keep a close eye on the boiler to see if the main burners turn OFF at any point, then re-light, or if they just keep on going until the header tank boils....

 

 

 

Will do and report back in the morning, have a hunch it will boil over but we will see.

[MtB]

2 minutes ago, Rickent said:

Will do and report back in the morning, have a hunch it will boil over but we will see.

 

Got a digital multimeter and know how to use it?

 

If/when it gets to boiling, measure the output voltage from the thermostat going to the gas valve, to see if it is zero or 12Vdc....

 

 

 

Or more specifically, measure the voltage right on the gas valve terminals. 

 

 

[Rickent]

10 minutes ago, Mike the Boilerman said:

 

Got a digital multimeter and know how to use it?

 

If/when it gets to boiling, measure the output voltage from the thermostat going to the gas valve, to see if it is zero or 12Vdc....

 

 

 

Or more specifically, measure the voltage right on the gas valve terminals. 

 

 

I do have a multimeter and know how to use it, but I have no idea of the workings of an Alde boiler, might be a quick learning curve coming up.

[MtB]

8 minutes ago, Rickent said:

I do have a multimeter and know how to use it, but I have no idea of the workings of an Alde boiler, might be a quick learning curve coming up.

 

Ok spend a while reading the manual, they are actually really simple and easy to grasp once you see the components involved. 

 

Find/identify the gas control valve, it will have two wires to it that can be either 12Vdc or 0Vdc. When 12Vdc this opens the gas flow to the burner. When 0Vdc the gas to the burner should shut off. I suspect yours does not shut off for a while when at 0Vdc, i.e. it sticks open for a random amount of time then shuts off. 

 

 

 

[Rickent]

2 minutes ago, Mike the Boilerman said:

 

Ok spend a while reading the manual, they are actually really simple and easy to grasp once you see the components involved. 

 

Find/identify the gas control valve, it will have two wires to it that can be either 12Vdc or 0Vdc. When 12Vdc this opens the gas flow to the burner. When 0Vdc the gas to the burner should shut off. I suspect yours does not shut off for a while when at 0Vdc, i.e. it sticks open for a random amount of time then shuts off. 

 

 

 

Cheers Mike, will get onto it in the morning and report back.

[MtB]

Just now, Rickent said:

Cheers Mike, will get onto it in the morning and report back.

 

Have a look at the manual, look at the wiring diagram in particular and come back with questions about anything not clear!
 

 

[dmr]

3 minutes ago, Mike the Boilerman said:

 

Ok spend a while reading the manual, they are actually really simple and easy to grasp once you see the components involved. 

 

Find/identify the gas control valve, it will have two wires to it that can be either 12Vdc or 0Vdc. When 12Vdc this opens the gas flow to the burner. When 0Vdc the gas to the burner should shut off. I suspect yours does not shut off for a while when at 0Vdc, i.e. it sticks open for a random amount of time then shuts off. 

 

 

 

Can you give us a link to this manual (assuming its on-line) ? I was looking for it only last week but couldn't find it. One of my plans (dreams) was to remove the Alde (that we never use) and fit a diesel heater, but with the days of Red Diesel now numbered I am starting to think that maybe I should keep the Alde and use it on the really cold winter days.

 

Due to this lockdown we are static for the first time in over ten years and I am starting to rethink solar power and heating options.

 

.................Dave

[MtB]

6 minutes ago, dmr said:

Can you give us a link to this manual (assuming its on-line) ?

 

https://www.manualslib.com/manual/559295/Alde-Comfort-2923-2928.html#manual

 

 

[dmr]

15 minutes ago, Mike the Boilerman said:

 

https://www.manualslib.com/manual/559295/Alde-Comfort-2923-2928.html#manual

 

 

Thanks

 

I did find this one but it looked a bit dodgy with random uppercase and lowercase letters in the screen display, but I have now saved a pdf and that looks fine.

 

..............Dave

[MtB]

18 minutes ago, dmr said:

Thanks

 

I did find this one but it looked a bit dodgy with random uppercase and lowercase letters in the screen display, but I have now saved a pdf and that looks fine.

 

..............Dave

 

Yes all their manuals have this and yes looks welldodgy!!

 

But they've been around a few years now and seem to have the best range of manuals of any of the libraries, and I've yet to have a problem with any of their content. Stupid format though. 

 

 

 

[Jess--]

the key to this may be that the radiator circuit is turned off leaving only the smaller calorifier circuit.

if there is any air in the system (which is common) then it may just be a case of not enough expansion room.

with mine when running normally (both circuits open) the level in the header tank used to stay between 2-3 inches (2 cold / 3 hot), with only the calorifier running (so no radiators dumping heat) it went from 2 inches cold up to the overflow pipe when hot.

 

a silly suggestion would be to turn down the gas setting, we only ran ours on 1 (2 if it was freezing temps) 3 and above had the heater sounding like a boiling kettle. 

[Rickent]

6 hours ago, Jess-- said:

the key to this may be that the radiator circuit is turned off leaving only the smaller calorifier circuit.

if there is any air in the system (which is common) then it may just be a case of not enough expansion room.

with mine when running normally (both circuits open) the level in the header tank used to stay between 2-3 inches (2 cold / 3 hot), with only the calorifier running (so no radiators dumping heat) it went from 2 inches cold up to the overflow pipe when hot.

 

a silly suggestion would be to turn down the gas setting, we only ran ours on 1 (2 if it was freezing temps) 3 and above had the heater sounding like a boiling kettle. 

We very rarely have the radiatior circuit open, and everything has been fine up to now, turning the setting down is an option but this is assuming the thermostat is working correctly, which is what I will check today.

[Tony Brooks]

Remember that within all this talk of thermostats that you have at least two thermostats. The boiler stat that's inside the boiler case and might be called the over heat device (see below) and the room thermostat. The room thermostat will have no direct effect ion the burner, the room stat only controls the pump so when up to temperature when the room stat cuts out the pump stops, the boiler temp rises to the point set by the knob with numbers on it and at the set point the burner cuts out. here it sounds as if the boiler is not cutting out.

 

The main boiler stat must be on the lower end of the rod fitted to the control knob but how it senses water temperature I have no idea, my manual is far from clear, the wiring diagram leaves a lot to be desired as well. Then there is what the manual describes as the overheat protection so even if the main boiler stats failed in the boiler on position the overheat protection should have cut the burner out.

 

I would take the cover cover off and be looking for a displaced electrical connection on the gas valve assembly as a first step. Also identify the overheat devise and make sure its still firmly against the boiler (heat exchanger) case.

[MtB]

17 minutes ago, Tony Brooks said:

Remember that within all this talk of thermostats that you have at least two thermostats. The boiler stat that's inside the boiler case and might be called the over heat device (see below) and the room thermostat.

 

The boiler control thermostat (with the adjustable knob on), the overheat protection thermostat (invisible to the user) are not the same device, they are two separate thermostats IIRC. And the room thermostat makes three thermostats on the system.

 

17 minutes ago, Tony Brooks said:

Also identify the overheat devise and make sure its still firmly against the boiler (heat exchanger) case.

 

Same comment about the sensor phial for the boiler control thermostat. In fact I've an idea both sensor phials are attached to the heat exchanger by the same metal strap/bracket. If the strap/bracket has broken and/or the two sensors are no longer held firmly against the heat exchanger, the exact symptoms the OP describes would happen. 

 

 

Edited April 11, 2020 by Mike the Boilerman

[Tony Brooks]

3 minutes ago, Mike the Boilerman said:

 

Three thermostats. Boiler control thermostat (with the adjustable knob on), the overheat protection thermostat (invisible to the user), and the room thermostat. These are three separate components. 

 

 

Same comment about the sensor phial for the boiler control thermostat. In fact I've an idea both sensor phials are attached to the heat exchanger by the same metal strap/bracket. If the strap/bracket has broken and/or the two sensors are no longer held firmly against the heat exchanger, the exact symptoms the OP describes would happen. 

 

 

Agreed and I THINK on mine that fixing was a coil spring holding them against the heat exchanger by just spring tension so rust or a good hard bang may well have displaced them.  I might be getting mixed up with a small thermostat on my son's old unreliable BG branded gas boiler though.

[MtB]

12 minutes ago, Tony Brooks said:

Agreed and I THINK on mine that fixing was a coil spring holding them against the heat exchanger by just spring tension so rust or a good hard bang may well have displaced them.  I might be getting mixed up with a small thermostat on my son's old unreliable BG branded gas boiler though.

 

Its two or three years since I saw one too, but I remember noting how crude and poor the method of holding the sensor phials in place was.

 

To help the OP, a description of a thermostat might be helpful. It is a mechanical device comprising a box with a switch inside (and two spade terminals) at one end, and a copper heat sensor phial on the other end, the two being connected by a thin copper capillary tube usually about two feet long. I'll bung up a photo of a generic thermostat in a sec to illustrate...

 

 

 

 

Here yer go...

 

Edited April 11, 2020 by Mike the Boilerman

[Rickent]

21 minutes ago, Mike the Boilerman said:

 

Its two or three years since I saw one too, but I remember noting how crude and poor the method of holding the sensor phials in place was.

 

To help the OP, a description of a thermostat might be helpful. It is a mechanical device comprising a box with a switch inside (and two spade terminals) at one end, and a copper heat sensor phial on the other end, the two being connected by a thin copper capillary tube usually about two feet long. I'll bung up a photo of a generic thermostat in a sec to illustrate...

 

 

 

 

Here yer go...

 

Just run the boiler without the pump running and after about 5 minutes, the full flame dropped down to pilot flame as it warmed up.

[MtB]

7 minutes ago, Rickent said:

Just run the boiler without the pump running and after about 5 minutes, the full flame dropped down to pilot flame as it warmed up.

 

Dammit. 

 

We have an intermittent fault then. And it's gone now. 

 

 

 

 

[Rickent]

48 minutes ago, Mike the Boilerman said:

 

The boiler control thermostat (with the adjustable knob on), the overheat protection thermostat (invisible to the user) are not the same device, they are two separate thermostats IIRC. And the room thermostat makes three thermostats on the system.

 

 

Same comment about the sensor phial for the boiler control thermostat. In fact I've an idea both sensor phials are attached to the heat exchanger by the same metal strap/bracket. If the strap/bracket has broken and/or the two sensors are no longer held firmly against the heat exchanger, the exact symptoms the OP describes would happen. 

 

 

The overheat sensor is clipped into the main body and is in place with the clip intact. 

The thermostat appears to be working.

I am now running the boiler on a lower setting, let's see how that goes. 

1 minute ago, Mike the Boilerman said:

 

Dammit. 

 

We have an intermittent fault then. And it's gone now. 

 

 

 

 

You know they are the worse kind.

[MtB]

5 minutes ago, Rickent said:

The overheat sensor is clipped into the main body and is in place with the clip intact. 

The thermostat appears to be working.

I am now running the boiler on a lower setting, let's see how that goes. 

You know they are the worse kind.

 

Yep. But this is still progress. We have ruled out the phial clip being busted.

 

We also know *something* is sticking ON when it is supposed to be OFF. My money is back on the gas valve failing to close when power is withdrawn. The two boiler thermostats are connected in series supplying power to the gas valve, so it would take both of them the jam ON at the same time to create this fault. Very unlikely.

 

 

[Rickent]

2 minutes ago, Mike the Boilerman said:

 

Yep. But this is still progress. We have ruled out the phial clip being busted.

 

We also know *something* is sticking ON when it is supposed to be OFF. My money is back on the gas valve failing to close when power is withdrawn. The two boiler thermostats are connected in series supplying power to the gas valve, so it would take both of them the jam ON at the same time to create this fault. Very unlikely.

 

 

Are the electrical connectors on the gas valve accessible by just removing the bottom outer cover ?

[MtB]

1 minute ago, Rickent said:

Are the electrical connectors on the gas valve accessible by just removing the bottom outer cover ?

 

Can't actually remember but almost certainly, yes.

 

The bottom cover is a right pain in the butt to remove and replace IIRC!