Central Heating 12v circulation pump

[mhember]

Hi,
Thank you for the information - really useful. I share your concern regarding the heat capacity from the 66M - although we never seem to have ours turned up at all beyond 'minimum' and it seems to kick out so much heat I feel like there should be enough for the cabins also! How big / what type of boat do you heat with your 66MS?

The hot plate point is really good - I'm trying to balance the simplicity of a stove which fits directly in our space with the need for more power output and the need to change the flue arrangements etc.

Yours aye

Marcus

 

[kitling89]

No worries, I remember how much of a process it was to set our system up.

We have a 40 ft insulated steel monohull with a large deck salon (Dix 38 Pilot). One radiator (462 W) in the v berth plus a towel bar (284W) in the head and the main stove in the saloon.

With that setup we tend to keep the boat around 18C down to external temp of -5C, maybe lower if the wind is calm or we put insulation on the large saloon windows.

As far as sizing, you probably already know but they run cleaner at >50% throttle so you don't want too large. But obviously it needs to big enough to keep up. I don't think fuel efficiency is radically different for a given heat output, though there seems to be some newer technology in the design of the 2000..

 

[mhember]

Thank you - really useful. Being able to use the same connections / footprint for our existing 66 is a bit of a consideration, trying to judge how much KW we need is hard! We have had electric radiators in the past when on shore power as a comparitor but hard to judge.

I'm guessing you used separate 'flow' and 'return' pipes so you could balance the radiators or are they just plumbed in series? What connections etc did you use?

 

[ghostlymoron]

To be honest, the flow rate of a central heating circulator doesn't seem to make much difference. Running the pump faster gives less time in the boiler for the water to heat up but it also gives less time in the radiators to cool down. Is your system vented or invented?

 

[BabaYaga]

To be honest, the flow rate of a central heating circulator doesn't seem to make much difference. Running the pump faster gives less time in the boiler for the water to heat up but it also gives less time in the radiators to cool down. Is your system vented or invented?

For a system with radiators in series, I think flow rate will mainly influence how balanced the heat distribution will be along the circuit.

 

[kitling89]

The radiators are in parallel (we only have two and they are mounted on either side of the same bulkhead) and we never fully shut the off the towel bar. Another advantage of the 2000 is it can be run dry in case you decide you don't want the radiator system or you have power failure for the circulation pump. Running the stoves with cooper coils (ie 66MS) dry will damage the copper.

I used plastic pipework and plastic push-fit connectors JG Speedfit Plastic Push-Fit Equal 90° Elbows 22mm 5 Pack underfloor where visible. The underfloor runs were covered in pipe insulation Coated Pipe Foam Insulation Polyethylene Lagging Tubing Wrap Red Blue 2m Lengths | eBay prior to installation to conserve heat in our uninsulated steel bilge.

Where visible we used stainless tails and stainless compression fittings to match the stainless radiators.

I agree the flow rate doesn't matter other than that slower means less noise and power usage from the pump. Think about how slow the convective systems must run and they still work fine...

Not sure what you mean by 'vented' but we do have a small expansion tank just downstream and above the output of the stove. But proper setup of the loop requires purging of air from all radiators to ensure proper heating. Allowing the system to breathe fresh air in and out sounds like a good way to encourage growth in the coolant.

 

[ghostlymoron]

The radiators are in parallel (we only have two and they are mounted on either side of the same bulkhead) and we never fully shut the off the towel bar. Another advantage of the 2000 is it can be run dry in case you decide you don't want the radiator system or you have power failure for the circulation pump. Running the stoves with cooper coils (ie 66MS) dry will damage the copper.

I used plastic pipework and plastic push-fit connectors JG Speedfit Plastic Push-Fit Equal 90° Elbows 22mm 5 Pack underfloor where visible. The underfloor runs were covered in pipe insulation Coated Pipe Foam Insulation Polyethylene Lagging Tubing Wrap Red Blue 2m Lengths | eBay prior to installation to conserve heat in our uninsulated steel bilge.

Where visible we used stainless tails and stainless compression fittings to match the stainless radiators.

I agree the flow rate doesn't matter other than that slower means less noise and power usage from the pump. Think about how slow the convective systems must run and they still work fine...

Not sure what you mean by 'vented' but we do have a small expansion tank just downstream and above the output of the stove. But proper setup of the loop requires purging of air from all radiators to ensure proper heating. Allowing the system to breathe fresh air in and out sounds like a good way to encourage growth in the coolant.

I meant header tank or pressurised only because I wonder how these systems are plumbed into a boat.

 

[mhember]

The radiators are in parallel (we only have two and they are mounted on either side of the same bulkhead) and we never fully shut the off the towel bar. Another advantage of the 2000 is it can be run dry in case you decide you don't want the radiator system or you have power failure for the circulation pump. Running the stoves with cooper coils (ie 66MS) dry will damage the copper.

I used plastic pipework and plastic push-fit connectors JG Speedfit Plastic Push-Fit Equal 90° Elbows 22mm 5 Pack underfloor where visible. The underfloor runs were covered in pipe insulation Coated Pipe Foam Insulation Polyethylene Lagging Tubing Wrap Red Blue 2m Lengths | eBay prior to installation to conserve heat in our uninsulated steel bilge.

Where visible we used stainless tails and stainless compression fittings to match the stainless radiators.

I agree the flow rate doesn't matter other than that slower means less noise and power usage from the pump. Think about how slow the convective systems must run and they still work fine...

Not sure what you mean by 'vented' but we do have a small expansion tank just downstream and above the output of the stove. But proper setup of the loop requires purging of air from all radiators to ensure proper heating. Allowing the system to breathe fresh air in and out sounds like a good way to encourage growth in the coolant.

That is great, thank you. I was considering using the same stuff, the JG Speedfit has a good rep and the flexible piping makes it easier through the bilges etc.
Really grateful for your taking the time to put this detail down - thank you!

 

[mhember]

Finally actually getting on with the installation after lots of time away with work and other distractions! I've purchased the 12VDC Hot Water circ pump from Ebay that you recommended on 5 Apr 22; looks good, and i'm using a DC-DC converter to run it at low power (5v). Flow seems ample on bench testing, it copes with back pressure, is nice and quiet, and is consuming about 180-190mA. Ideal. Rads, pipe, bulkhead connections etc going in.

I've attached latest scribbles of layout - although counter to this drawing I think I'm going to put the rads in parallel not series so I can adjust heat output more / close one to emphasise the other. Header tank and some pipework will be in the other cabin which will add heat in there also.

The I've looked at the Adle heat exchanger (for engine heat to HW tank and rads), however they are pricey, quite hard to connect with. There is another option - https://www.ebay.co.uk/itm/193349721937 - 25KW version with insulation - which will be way over spec but size / fitting / setup etc wise seems good. It is not intended for on - engine use however the temperature parameters, limits, pressures etc are all well within parameters so I'm hopeful that might do the trick. Anyone used one of these? Or should I go for the Alde?

Thanks for the details you offered - been useful!

Marcus

 

[mhember]

This is as installed, now it is all complete. Very successful with the 66M, hot radiators and hot water working nicely. Heat exchanger also fine and well within it's performance spec.
Thank you for the hint on the pump which is neat, small, and quiet.