Alde Boiler Wiring

[GSer]

We used to have an old style Alde boiler fitted in our boat, this, after a few years good reliable service, started to fail, so I removed it to see what could be done to renovate it, after inspection I decided that a new room sealed flue type would be the best way to go.

 

So I saved up the cash and fitted a new boiler and chimney, then I came to wire it up and it was obvious the original boiler had been modified over the years and the wiring was very different. The old boiler loom had been discarded with the old boiler.

 

I paid a gas guy to come in and check the installation was safe and he offered to wire it all up, fantastic, the boiler worked fine and I was happy.

 

This weekend I've just turned up at our winter moorings, and I want to use the boiler to give me hot water rather than to heat the boat (i use solid fuel for general cabin heating and normally run the engine for electrics and get hot water as a handy by product)

 

In the past with the old boiler I flicked a switch on the side of the boiler and that activated the calorifier thermostat, and thats the wiring i'm now missing.

 

What is happening now is the room thermostat is switching the boiler off before any hot water is created and if I leave the cabin with no heating (no fire lit and the rads turned off) the aldi keeps running 24/7 if i left it to its own devices.

 

What I need is a simple wiring diagram showing how I should wire both thermostats and i would guess a switch so I can achieve thermostat controlled hot water and no room heating if I so wish?

 

Cheers

 

Paul

 

 

ps Perhaps I'd be better off buying a calorifier with an immersion heater fitted?

[dor]

I assume you are talking about the 2928 comfort boiler.

 

I just put a switch in the circuit to switch on the pump. I had full-flow ball valves to control whether the boiler heated rads, calorifier or both. If you switch the pump independently, you also have the advantage that you can use the calorifier as a heat exchanger and use the engine to heat your rads while under way.

[Ray]

I did similar but recently have wired the calorifier thermostat in series with the switch so that once the cylinder comes up to temperature the boiler switches off - think I may have positioned the thermostat a bit too low though, so need to work on getting the temperature right.

 

I'm now considering a further modification whereby I have an electric valve of a type yet to be decided that will either shut off the supply to the cylinder or the rads when the relevant thermostat says so. Indeed, it may end up being two valves, one in each circuit so that I have more control.

[dor]

I'm now considering a further modification whereby I have an electric valve of a type yet to be decided that will either shut off the supply to the cylinder or the rads when the relevant thermostat says so. Indeed, it may end up being two valves, one in each circuit so that I have more control.

 

I considered this, but couldn't find a 12V zone valve at anything like sensible cost. So I just relied on the internal Alde thermostat to shut it down. A stat on the cal just connected to the pump motor should do the trick.

[Guest TerryL]

I considered this, but couldn't find a 12V zone valve at anything like sensible cost. So I just relied on the internal Alde thermostat to shut it down. A stat on the cal just connected to the pump motor should do the trick.

 

Why not wire it as a standard Y or S plan heating system using 230 volt motor valves and run on a small inverter? The time switch should be battery operated though because the mains type are usually switch mode and don't like cheap square wave or sometimes modified sine wave inverters. A 12 volt pump could be run through a relay.

[Big COL]

I considered this, but couldn't find a 12V zone valve at anything like sensible cost. So I just relied on the internal Alde thermostat to shut it down. A stat on the cal just connected to the pump motor should do the trick.

 

Hi Dor

 

Tee piece fitting and two 12v mag valves = A 12v zone valve. Or if you could live with a priority zone control you could use a drayton thermal bypass valve no electrics involved.

Edited October 28, 2008 by Big COL

[dor]

Hi Col.

 

In the end it didn't seem worth the bother. FDIdn't particularly want an inverter on all the time and the manual lever ball valves were easy enough to use.

[Ray]

Excuse me folks, how does a 12v mag valve work - I understand that it uses 12v! - and where can you get them?

[Big COL]

Excuse me folks, how does a 12v mag valve work - I understand that it uses 12v! - and where can you get them?

 

Hi Ray

 

A 12v mag valve when energised will open the port and allow the water to flow. De-energise and the valve will close stopping the flow.

Source of supply any electrical wholesalers, major plumbing merchants, or on line.

[Ray]

Sorry for yet another question. Will any type do?

 

I've been quoted around £85 for a 12v valve and this seems a bit excessive as I may need two.

[Big COL]

Sorry for yet another question. Will any type do?

 

I've been quoted around £85 for a 12v valve and this seems a bit excessive as I may need two.

 

Ray

Try a google search for 12volt water solenoid valves. A lot of washing machines and dishwashers have 12v water inlet valves on them, a visit to the local tip or scrap yard may be worthwhile. You should be able to source a new one for around £20.

[GSer]

Many thanks for all the replies, but still no nice simple wiring diagram for me to try and understand.

 

Paul

[Ray]

Not sure that I could get a diagram uploaded, so I'll try and explain how you would need to wire it.

 

There should be a 12v supply to the terminal block on the top of the Alde (1). From memory you connect one side of the room thermostat to this supply and then the other wire from the thermostat goes to different termination pont (2) on the terminal block from whence a wire goes to the pump on the Alde. Thus, when the room thermostat contacts close because it is too cold, the circuit is made and the pump starts up. Because the pump is circulating cold(er) water around the boiler (to start with) the internal thermostat in the Alde now closes, this fires the boiler and the water starts to heat. If the boiler overheats the water in the boiler itself, the internal thermostat opens and the boiler shuts down until the pump has managed to disperse the hot water, replacing it with colder water coming back round the system. the internal thermostat that closes again, the boiler fires, and so it goes on.

 

That, as I understand it, is the basic operation of the Alde (and probably most boilers found on boats).

 

What I have done on our boat is to take a second wire from the 12v connector on the Alde termination block (1), and run this to a cylinder thermostat. The other wire from the cylinder thermostat returns to an illuminated switch which I can turn on or off, depending on whether I want hot water heated by the Alde or via the engine. The other wire from the switch goes to termination point (2) on the Alde. The switch is illuminated to remind me when it is switched on (and the boiler running - the switch won't be lit when the cylinder thermostat is open)

 

Either thermostat can now fire the boiler/pump. Rather than have heated water passing through the radiators when we just want warm water for washing, I have a T off the (plumbing) output from the Alde. One leg of the T leads to the radiators via a gate valve and the other leg of the T leads to the cylinder, again via a gate valve. I always have one gate valve open. I also have a T in the return side of the plumbing with one leg connected to the cylinder and the other to the radiators.

 

What I want to do, because the gate valves aren't easily accessible, is to replace the two gate valves with magnetic valves, which I can possibly connect to the thermostat as well, either directly or via a relay. Thus, when one thermostat calls for heat, the appropriate valve opens and the boiler switches on and warms that circuit. If the other thermostat calls for heat the other valve opens and that gets heat either at the same time, if both valves are open, or separately if only one valve is open.

 

One word of warning for anyone thinking of copying this idea and fitting a cylinder thermostat to a two coil calorifier. We have the bottom coil of the calorifier connected to the engine to provide the maximum amount of hot water when we're cruising. We've connected the top coil of the calorifier to the Alde. However, when we fitted the cylinder thermostat, we followed the positioning instructions that came with the thermostat and placed it too near the bottom of the cylinder. Because hot water rises quicker (in the cylinder) than it sinks, and the cylinder thermostat has a three degree range between opening and closing, the pump keeps going for a lot longer than we'd expected when it is trying to heat the calorifier, simply because the thermostat is positioned too low and the water at the bottom of the cylinder doesn't heat quick enough.

 

Unfortunately, we can't simply move the thermostat because we had to cut out a lump of insulation where we wanted the thermostat to go and don't fancy opening up yet another area of the insulation to move the thermostat.

 

We need to look closely at the thermostat to see if we can reduce the temperature range between open and closed and then adjust the temperature so that that thermostat will trip in and out at a lot lower cylinder temperature. A temperature that will probably be reached quicker than waiting for the water to reach the same temperature at the top and bottom of the cylinder.

 

On a separate point, we've had problems with the water in the cylinder not staying warm overnight if we use too much in the evening - by too much, we mean enough for washing up. A colleague has suggested that we might be able to slow the cooling down if we add a insulation jacket over the foam insulation that the cylinder already has. Our colleague says that he's done this at home with significant benefit.

 

Hope the above helps.

[frangar]

Ray

 

Just a thought but if you want to move the cylinder stat then you could cover the hole left by using some of that insulating foam in aerosol stuff.

 

Also you might be losing heat overnight through the engine thermo cycling thro its coil...its what happens on our boat and the next time i drain the engine antifreeze I'm going to fit a flap valve into the engine to calorifier line to hopefully stop it. You can easily check this by seeing if the top of the engine feels warm when just the alde is running.

 

Hope this helps

 

Gareth

[GSer]

Hope the above helps.

 

 

Brilliant, thanks, that must have took some time to type with one finger, and I really appreciate your efforts

 

Paul

[Ray]

Ray

 

Just a thought but if you want to move the cylinder stat then you could cover the hole left by using some of that insulating foam in aerosol stuff.

 

Also you might be losing heat overnight through the engine thermo cycling thro its coil...its what happens on our boat and the next time i drain the engine antifreeze I'm going to fit a flap valve into the engine to calorifier line to hopefully stop it. You can easily check this by seeing if the top of the engine feels warm when just the alde is running.

 

Hope this helps

 

Gareth

 

Gareth

 

Yes, we could use the spray foam. I haven't totally ruled it out but I don't think it is as dense as that on the rest of the cylinder. Mind you, something is better than nothing.

 

We already have a non-return valve in the circuit.

 

If we draw a couple of litres through the tap - which is not the same as saying drawing a couple of litres of hot water off the cylinder, due to the long run between cylinder and tap - the water is still reasonably warm enough in the morning for a shower. We can even get away with drawing about 4 litres off, although the water is a tad cooler in the morning. Draw nothing and it is a lot warmer but still nowhere as hot as it is whilst the engine's running, which is toooooo hot. Do the washing up and the water's barely tepid by morning (and its a 55 litre cylinder).

 

I need to get a thermometer and take that with us next time we go cruising so that we can measure the temperature at various times.

 

Thanks for the suggestions.

[Ray]

I managed to locate two magnetic valves for £38, including £5 VAT and postage of a similar amount.

 

They only arrived today. I want to check current usage - suggested about 0.5amp each - before I fit them, which will probably be in a couple of weeks as we're hoping to cruise next weekend and I don't fancy draining down and everything else before we go and then finding I have an airlock. Leaving it until afterwards gives me all winter to resolve any difficulties.

 

I'll let you know how well they work and what the actual current consumption is.

 

Out of interest, is there anyway I can fit them without draining down?

[Ray]

Checked the valves this morning with a bog standard digital multimeter. Current consumption when fed from a 13.8v transformer was .54 amps.

 

However, I'm slightly worried. Although the valve "clicked" when current was applied, and "clicked" again when the power was removed, looking throught the orifice didn't seem to reveal any moving parts.

 

Then I remembered that the salesman had told me that the valves only worked at 0.2Bar. Completely forgetting what I was going to use them for, I said that would be OK because my system was running at about 1.6Bar. Yep, momentarily, I'd thought I was fitting these valves into the main water supply where the water pump is rated at 1.6Bar.

 

Instead, I'm using the valves with the Alde's pump and I have no idea what the pressure is that builds up. The last thing that I want to do is fit these (normally closed) valves and find that they won't open because the water pressure isn't sufficient. Have I made a mistake and bought valves that won't do what I wanted them to do?

[frangar]

Possibly Ray!

 

I think the Alde pump might be a bit pushed to get to .2 Bar (3psi)......maybe you could rig up a test loop before fitting properly?? As I understand it the pump is there just to help the convection which is why the current draw is so low.

 

Maybe someone else can verify??

 

Cheers

 

Gareth

[Ray]

Ray

 

Just a thought but if you want to move the cylinder stat then you could cover the hole left by using some of that insulating foam in aerosol stuff.

 

Gareth

 

I've decided that I will re-position the thermostat and use spray foam to refill the hole I cut in the foam around the calorifier, although it

will probably be Christmas before I get round to doing it.

 

We originally fitted the stat about a third of the way up the cylinder (from the bottom) as advised in the instructions with the stat. Has anyone any idea where it should be moved to - position wise - relative to the position of the top coil connection on the calorifier?