Thermostatic Calorifier valve

[Supertramp]

Recent topics have helped with planning my boiler change, and mentioned thermostatic valves to stop the system working in reverse when the fire is low, otherwise the hot calorifier will try and heat the radiators and stove.

 

Simple question, - what type of valve, and where does it go?

 

(solid fuel stove,> 3 medium rads,> 12v pump,> calorifier with twin coils and immersion heater, mostly 240v hookup available)

 

Thanks

 

Tony

[steelaway]

Recent topics have helped with planning my boiler change, and mentioned thermostatic valves to stop the system working in reverse when the fire is low, otherwise the hot calorifier will try and heat the radiators and stove.

 

Simple question, - what type of valve, and where does it go?

 

(solid fuel stove,> 3 medium rads,> 12v pump,> calorifier with twin coils and immersion heater, mostly 240v hookup available)

 

Thanks

 

Tony

 

 

 

Hi

 

See.............Surejust

 

Alex

[Supertramp]

Hi

 

See.............Surejust

 

Alex

Thanks Alex, - from the long list, - is it Therm-22 22mm thermostatic mixer valve £45.50 ? - I'm still unsure how it plumbs in?

[Keeping Up]

Beware that some thermostatic mixer valves include a "safety" shut-off that closes it down completely if the hot water temperature exceeds 80 degrees. The Caleffi for example is one such, and I spent a long time wondering why my hot water supply kept failing after the engine had been running for an hour.

[ditchcrawler]

Thanks Alex, - from the long list, - is it Therm-22 22mm thermostatic mixer valve £45.50 ? - I'm still unsure how it plumbs in?

Surely its not a mixer valve that you want, that mixes cold water with hot before delivering it to the taps.

 

Recent topics have helped with planning my boiler change, and mentioned thermostatic valves to stop the system working in reverse when the fire is low, otherwise the hot calorifier will try and heat the radiators and stove.

 

Simple question, - what type of valve, and where does it go?

 

(solid fuel stove,> 3 medium rads,> 12v pump,> calorifier with twin coils and immersion heater, mostly 240v hookup available)

 

Thanks

 

Tony

If its a pumped secondary system,if the pump is not running how will the water flow round the rads?

[Supertramp]

Thanks for the replies so far, - although I'm not sure I've got an answer yet.

 

I thought it was a simple question, - perhaps I should add more detail.

 

Back boiler stove at front of boat (yes I know...) flow and return pipes feed 3 radiators down the boat,a 12v pump half way down runs continuously when the fire is in. and then into the engine room where the calorifier is. The flow and return feed into one of the calorifier coils, (almost like an 'end of line' radiator)

 

Just before the calorifier, there is a link pipe between flow and return with a stopcock on it, - it's normally open, thereby (i think) bypassing the calorifier, closing the stopcock would force the flow/return through the calorifier.

 

I dont want to switch off the pump, I just want a way of the water being directed into the calorifier if it's hotter than whats already there, and more important - not to pump cooler water around the calorifier when the fire is low,

 

Surely it's a common request?

 

Tony

[Tony Brooks]

Thanks for the replies so far, - although I'm not sure I've got an answer yet.

 

I thought it was a simple question, - perhaps I should add more detail.

 

Back boiler stove at front of boat (yes I know...) flow and return pipes feed 3 radiators down the boat,a 12v pump half way down runs continuously when the fire is in. and then into the engine room where the calorifier is. The flow and return feed into one of the calorifier coils, (almost like an 'end of line' radiator)

 

Just before the calorifier, there is a link pipe between flow and return with a stopcock on it, - it's normally open, thereby (i think) bypassing the calorifier, closing the stopcock would force the flow/return through the calorifier.

 

I dont want to switch off the pump, I just want a way of the water being directed into the calorifier if it's hotter than whats already there, and more important - not to pump cooler water around the calorifier when the fire is low,

 

Surely it's a common request?

 

Tony

 

 

It is probably a common wish but somehow I doubt it would get as far as request very often.

 

The first problem is that if you want it automatic then I think you will be looking for a 12v motorised valve unless you are happy running it via an inverter.

 

The next thing is that you want to do comparisons between water temperatures across a range and also set limits to accommodate the low stove temperature thing.

 

I am sure it could be done with a couple of thermistors (temp. sensors as per temperature gauges, a small computer (PIC?) to do the comparisons, one or two relays and the motorised valve but it needs technical knowledge and a source for the parts.

 

If you were happy simply setting thresholds I think a couple of pipe/cylinder stats, relays and motorised valve would do. There would be no need for the relays if you were using AC.

[Robbo]

Recent topics have helped with planning my boiler change, and mentioned thermostatic valves to stop the system working in reverse when the fire is low, otherwise the hot calorifier will try and heat the radiators and stove.

 

Here's what ya after..

 

http://www.honeywelluk.com/products/Valves/Other-Valves/VT100112R/

 

If you look at the reference guide it will show you how it's plumbed in.

 

Edit to add; doesn't require electric, works on the same principal of a radiator thermostatic valve, but has a remote sensor to stick on the clarifier.

 

Another edit; You may want to plumb it this way, with the 3 port valve and using the sensor on the pipe (between the fire and valve) so when the pipe is hot it sends it the clarifier, if cold back back to the return pipe.

Edited September 11, 2011 by Robbo

[Smelly]

Are you sure you need it?

 

If the return pipe descends from the Calorifier it'll stop any reverse thermosyphon dead in it's tracks, and even if your fire's low the BB will be rather hot and hence at a higher differential pressure to the Cal; again stopping any thermosyphon.

 

Sounds like a lot of money and hard work where you could rely on simple physics instead.

 

ETA: must read harder... sorry!

Edited September 11, 2011 by Smelly

[Tony Brooks]

Here's what ya after..

 

http://www.honeywelluk.com/products/Valves/Other-Valves/VT100112R/

 

If you look at the reference guide it will show you how it's plumbed in.

 

Edit to add; doesn't require electric, works on the same principal of a radiator thermostatic valve, but has a remote sensor to stick on the clarifier.

 

Another edit; You may want to plumb it this way, with the 3 port valve and using the sensor on the pipe (between the fire and valve) so when the pipe is hot it sends it the clarifier, if cold back back to the return pipe.

 

Its a neat idea but surely that will only open and close the flow to the calorifier according to calorifier temperature or, if the probe was fitted to a pipe the boiler temperature.

 

I understood the OP said they wanted to shut the flow off to the calorifier in two cases.

 

1. When the calorifier was up to a certain temperature (which this item will do).

 

2. When the boiler water was cooler than the calorifier and I am still trying to work out how this one would be achieved. Perhaps two such valves?

[atsoft22]

Hi everyone,

 

I believe this to be a very common problem and am proposing designing some electronics to resolve it as I need something similar. If you are interested pls contact me via email as I will be able to supply the electronics (non profit)and can advise where to source the Valve.

 

Simply, the functionality is a 12V motorised 2 port valve that is turned off when:- water in calorifier is up to temperature, or water in coil is lower temperature than water in Calorifier. (values to be configurable by user)

 

I have sourced a motorised valve that doesn't require power to stay open and the electronics will do the rest (relays, pic, thermistor inputs etc.) My speciality is the design of low powered electronics so this unit will consume very little of our valuable boat power. (I don't have shoreline and rely on solar and engine for power.)

 

Do hope there's some interest and any other suggested features so I can get this right for everyone's requirements.

 

Regards

[George94]

It's infuriating. The VT112R diverts the flow when the calorifier reaches a suitable temperature. What we need is something that diverts the flow until the water in the pipe reaches a suitable temperature.

 

I wonder if it can be modified. And how does the temperature sensor control the valve without using electricity?

[smileypete]

It's infuriating. The VT112R diverts the flow when the calorifier reaches a suitable temperature. What we need is something that diverts the flow until the water in the pipe reaches a suitable temperature.

 

I wonder if it can be modified. And how does the temperature sensor control the valve without using electricity?

 

What are you trying to do exactly?

 

cheers, Pete.

~smpt~

[Robbo]

Recent topics have helped with planning my boiler change, and mentioned thermostatic valves to stop the system working in reverse when the fire is low, otherwise the hot calorifier will try and heat the radiators and stove.

 

Simple question, - what type of valve, and where does it go?

 

(solid fuel stove,> 3 medium rads,> 12v pump,> calorifier with twin coils and immersion heater, mostly 240v hookup available)

 

Thanks

 

Tony

 

Sounds like you need one of these..

 

http://www.stovesonline.co.uk/wood_burning_stoves/ESBE-load-valves.html

 

 

 

VTC thermostatic valves are 3-way thermostatic valves. Installed close to the boiler stove or log gasifiyer the load valve protects the boiler from low return temperatures, improves efficiency and accumulator loading. When the water in the stove boiler is still cool the valve directs the water straight back to the stove. This means that the volume of water which the stove initially has to heat up is small and so it heats it up quickly.

When the water hits 60ºC the valve starts to open and lets a little of the water from the central heating return pipe into the boiler circuit, which of course lets a little hot water out into the central heating flow pipe. The valve gradually opens until by the time the water has reached 70ºC it is fully open and all the water is pumped into the central heating circuit. So in this way using a VTC series thermostatic valve gets the stove boiler up to temperature fast and keeps it there. This prolonges the life of the boiler, makes the stove work more efficiently, and reduces unnecessary mixing in accumulator tanks - because on hot water is allowed out into the main heating loop.

Edited November 22, 2013 by Robbo

[smileypete]

Hopefully Supertramp has his heating sorted by now, would have been a couple of cold winters otherwise

 

cheers, Pete.

~smpt~

[George94]

 

What are you trying to do exactly?

 

cheers, Pete.

~smpt~

 

My (solid fuel) boiler is at the back of the boat, and the calorifier near the front (I didn't design it!). When the boiler starts up, it sends hot water to the calorifier. So far, so good.

 

But by the time the hot water reaches the calorifier, it has cooled considerably, and may be at a lower temperature than the calorifier water. It will then cool the latter, rather than heating it.

 

So I want to be able to divert the water back to the boiler until it's hot enough.

 

The problem is that automotive diverter valves tend to operate at 80/90 degrees, not 50/60.

 

Sounds like you need one of these..

 

http://www.stovesonline.co.uk/wood_burning_stoves/ESBE-load-valves.html

 

 

 

 

Exactly what I need, but the price is a bit of a bummer. Those for cars are much cheaper.

 

Many thanks.

[Tony Brooks]

I suspect you will do a lot of work for little gain because although the boiler may be up to temperature as soon as you allow the hot water into the calorifier coil pipe cold water will come from the return and cool the boiler.

 

If you want to mess about put a pipe stat on the boiler output pipe controlling a 12V circulation pump on the calorifier feed pipe. Then when the pipestat is hot it will start the pump and as cool water flow through the boiler it will shut off.

 

I think that you may do better by adding good quality pipe insulation.

[smileypete]

Yeah as Tony says is the calorifier gravity fed or pumped?

 

Hopefully the latter, if so a solar rated TMV (thermostatic valve) will do it, some go up to 65°C, and can sometimes be had for £15-30ish on Ebay.

 

cheers, Pete.

~smpt~

Edited November 22, 2013 by smileypete

[George94]

I suspect you will do a lot of work for little gain because although the boiler may be up to temperature as soon as you allow the hot water into the calorifier coil pipe cold water will come from the return and cool the boiler.

 

If you want to mess about put a pipe stat on the boiler output pipe controlling a 12V circulation pump on the calorifier feed pipe. Then when the pipestat is hot it will start the pump and as cool water flow through the boiler it will shut off.

 

I think that you may do better by adding good quality pipe insulation.

 

I am not sure I follow you.

 

There is a already a 12v circulation pump, which starts up when the boiler is hot enough. It will then pump water to the calorifier, then the radiators, then back to the boiler.

 

However, it is a long pipe run from boiler to calorifier, and I want to avoid the cold water in that long run from being pumped through the calorifier. I want a bypass valve to divert it to the radiators and back to the boiler. After a while of this, the water in the pipe will be hot enough to be worth putting through the calorifier.

 

At the moment what is happening is that the cold water is cooling down the calorifier, and the calorifier's heat is being transferred to the radiators.

 

I am not losing any heat overall, but this process slows down the heating of the calorifier considerably. I can live with a cold cabin for a while (I have a separate fire in the saloon anyway) but I am not partial to cold showers.

 

The part of the pipe that can be lagged easily already has been.

Yeah as Tony says is the calorifier gravity fed or pumped?

 

Hopefully the latter, if so a solar rated TMV (thermostatic valve) will do it, some go up to 65°C, and can sometimes be had for £15-30ish on Ebay.

 

cheers, Pete.

~smpt~

 

I have been looking and looking for such valves, but with no joy. It doesn't help that some people call them by strange names. The one Robbo linked to is called a Load Valve.

 

ETA: I don't see how a mixer valve can help. I need cold water diverted elsewhere. I don't want anything mixed.

Edited November 22, 2013 by George94

[smileypete]

There is a already a 12v circulation pump, which starts up when the boiler is hot enough. It will then pump water to the calorifier, then the radiators, then back to the boiler.

 

Hmm, are the rads in parallel with the calorifier.... or in series?

 

Is it acceptable to prioritise the calorifier over the rads until it's heated up?

 

It may well be the backboiler output isn't enough to heat the calorifier all that well while the rads are on.

 

cheers, Pete.

~smpt~

Edited November 22, 2013 by smileypete

[Tom and Bex]

I've been thinking of solving this using a solar pump controller circuit from www.reuk.co.uk and a 12v motorised valve from eBay. Basically the circuit can compare the temp of the input pipe and the temp of the calorifier and could be connected up to a 12v motorised valve to send water via the calorifier if the input pipe is hotter or bypass the calorifier if that is hotter.

 

This should solve the problem we currently have of the pump from the fire pumping the hot water from the calorifier round the radiators overnight and cooling it down as the fire cools down.

 

This is just my thinking at the moment and can't see why it won't work but open to suggestions. I'm surprised more people don't have this problem to be honest.

 

Tom

[smileypete]

I've been thinking of solving this using a solar pump controller circuit from www.reuk.co.uk and a 12v motorised valve from eBay. Basically the circuit can compare the temp of the input pipe and the temp of the calorifier and could be connected up to a 12v motorised valve to send water via the calorifier if the input pipe is hotter or bypass the calorifier if that is hotter.

 

This should solve the problem we currently have of the pump from the fire pumping the hot water from the calorifier round the radiators overnight and cooling it down as the fire cools down.

 

This is just my thinking at the moment and can't see why it won't work but open to suggestions. I'm surprised more people don't have this problem to be honest.

 

The answer is in the explanation Tony Brooks kindly posted just above in post #17

 

For a pipe stat; most 'strap on' cylinder stats can be used, can sometimes be had on Ebay for £5-10.

 

cheers, Pete.

~smpt~

Edited November 23, 2013 by smileypete

[Tony Brooks]

If you go down the pipe-stat route please fit a manual switch in parallel with it. That way you will be able to start the pump if the stat fails, especially with a solid fuel stove.

[George94]

Hello

 

Hmm, are the rads in parallel with the calorifier.... or in series?

 

Is it acceptable to prioritise the calorifier over the rads until it's heated up?

 

It may well be the backboiler output isn't enough to heat the calorifier all that well while the rads are on.

 

cheers, Pete.

~smpt~

 

Hello Pete,

 

As stated, it heats the calorifier, then the rads, so it is serial.

 

I think one thing that is exacerbating the problem is that my boiler takes an age to get going. During that time (often several hours, unless I use wood) the water in the pipe from boiler to rad has time to cool down between cycles.

 

Cool water in the pipe then cools the calorifier.

 

Anyway, I have a diverter valve on order, and a circuit that compares temperatures and controls a relay to switch the valve on and off. That should cure the problem, but a simple 3 way thermostatic valve like the one on the engine would be simpler and better.

 

A better boiler would help too.

[smileypete]

Hmm gotta think about this one...

Edited November 24, 2013 by smileypete