Results 1 to 15 of 15

Thread: Coolant circulating pump

  1. #1
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,269

    Default Coolant circulating pump

    Iíve been using a 400w 115v block heater on my engine (Detroit 3-71) in winter. It not only helps immensely with cold weather starts, but it also adds a little heat to the boat to help drive out moisture. I love it when it works, but every two or three years it burns out and has to be replaced. The replacement process is a nightmare, the worst possible place to get an arm to hold a wrench that I have ever seen in all my years wrenching. So Iím looking at alternatives.

    I have a 15 gallon domestic water heater that is heated both by 115v shore power at the dock, and engine heat at sea. This means that while at the dock the engine coolant coil inside the water tank is sitting idle in 190 degree water. Seems like if I put a circulating pump on the engine coolant loop it would heat the engine.

    To do that, I wonder what type of pump one would use, and what would the monthly cost comparison be between the constant 400w block heater and the additional cost of heating the domestic water as it is cooled by the cold engine. And would this pump run continuously without wearing out. Anyone use a system like this?

  2. #2
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    25,508

    Default Re: Coolant circulating pump

    Can you set it up to thermosiphon? That way no pump would be needed.

    IOW - the solar collector below is your heater & the tank is the engine:



    Most automotive style coolant pumps will be 12 volt: https://www.autohausaz.com/pn/039202...MaAq4BEALw_wcB
    "If it ain't broke, you're not trying." - Red Green

  3. #3
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,269

    Default Re: Coolant circulating pump

    12v wouldn’t be a problem I suppose, the refrigerator is 12v and runs on the house bank being constantly charged by shore power. But I wonder about 24/7 constant duty of a pump. I also wonder why it doesn’t thermosiphon now but it may be that the engine’s 180 degree thermostat prevents it, which may also be a problem with the pump idea.

  4. #4
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    2,827

    Default Re: Coolant circulating pump

    Following with interest as I have a nearly identical setup but without the block heater. Seems like something worth adding though.

  5. #5
    Join Date
    Nov 2011
    Posts
    5,425

    Default Re: Coolant circulating pump

    You might consider a thermostatically controlled water pump from a household hot water heat system. I expect that they're very durable, and they're designed to pump hot water. Maybe someone here will have some ideas on how to incorporate the thermostat. I would just insulate the engine compartment and add a household thermostat. If the insulation were left in place all year it would help with sound proofing.

  6. #6
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,269

    Default Re: Coolant circulating pump

    Quote Originally Posted by cstevens View Post
    Following with interest as I have a nearly identical setup but without the block heater. Seems like something worth adding though.
    Which boat? if you have a relatively easy access 3/4” unused plug on your engine block (most engines do, sometimes under a diamond shaped cover plate), I would highly recommended the 400w block heater. It’s only about $50 so if it burns out every two or three years, no big deal IF, IF you have easy access to change it. I’ll probably stay with it unless the pump idea works, but I went down to change it today and even with my notes from last time, I gave up after my aged body would no longer put up with the required contortions.

    1DE8D901-3A25-446A-88FA-BEEEFC7767B4.jpeg

  7. #7
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    25,508

    Default Re: Coolant circulating pump

    A block heater (as Ron pictured) is by far the most efficient way to heat an engine. Generally they use 1/3 or less power than a tank type.
    "If it ain't broke, you're not trying." - Red Green

  8. #8
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    2,827

    Default Re: Coolant circulating pump

    Well, both, but thinking of Skookum Maru specifically. Good thought on the block heater though. I’ll have to have a look this weekend when I’m back in Blaine. And in the meantime this:

    http://www.suremarineservice.com/Hea...ECUSTOMERPRICE

    might be useful?

  9. #9
    Join Date
    Apr 2005
    Location
    Hills of Vermont, USA
    Posts
    25,508

    Default Re: Coolant circulating pump

    Gotta make sure any circ pump can handle 200 deg. liquid.
    "If it ain't broke, you're not trying." - Red Green

  10. #10
    Join Date
    Oct 2005
    Location
    seattle
    Posts
    14,269

    Default Re: Coolant circulating pump

    Thanks for the link Chris. I always seem to forget about Sure Marine. Odd given that they are sure close . I’ll talk to them tomorrow.

  11. #11
    Join Date
    Apr 2010
    Location
    South Australia and Tasmania
    Posts
    15,479

    Default

    Any pump designed for solar hot water systems will do I'd have thought.


    Sent from my iPhone using Tapatalk

  12. #12
    Join Date
    Apr 2000
    Location
    Southampton Ont. Canada
    Posts
    6,286

    Default Re: Coolant circulating pump

    It sounds like one of these would do

    http://www.canadiantire.ca/en/pdp/ci...-0303295p.html

    It gets cut into a heater hose(3/4"-1") at a low spot so that it doesn't run dry.
    Little fuss to change it if it dies.
    In the winter, our loader (JCB 520-50) gets plugged into a receptacle thats downstream of a timer that comes on a 5am and goes off at 10am
    30 minutes at -20C, and it's is good to go.
    R
    Sleep with one eye open.

  13. #13
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    2,827

    Default Re: Coolant circulating pump

    Quote Originally Posted by Ron Williamson View Post
    It sounds like one of these would do

    http://www.canadiantire.ca/en/pdp/ci...-0303295p.html

    It gets cut into a heater hose(3/4"-1") at a low spot so that it doesn't run dry.
    Little fuss to change it if it dies.
    In the winter, our loader (JCB 520-50) gets plugged into a receptacle thats downstream of a timer that comes on a 5am and goes off at 10am
    30 minutes at -20C, and it's is good to go.
    R
    That is interesting, except that I don't think it's a pump? According to the Phillips/Temro website:

    Most of these heaters heat and circulate the coolant by Thermal Siphoning. Thermal siphoning refers to the process of heated coolant rising, thereby drawing cooler coolant in to replace the warm coolant. The only Circulation Heater that has a pump is the Forced Flow Circulation Heater.
    Seems like that's pretty much just what the block heater is doing already? Although the external heater might be easier to change out in Ron's case.

    This is the forced flow pump:

    https://www.amazon.com/Zerostart-Tem.../dp/B01MFCHX8G

    Which does seem like a better option than the pumps from Sure Marine. Pricing is similar but it's a heater and a pump combined in one unit.

  14. #14
    Join Date
    Apr 2000
    Location
    Southampton Ont. Canada
    Posts
    6,286

    Default Re: Coolant circulating pump

    More like a coffeemaker than a plain thermosiphon.
    Mine is cut into the heater hose,and feeds toward the block.
    It comes out of the block and goes to the heater core in the cab,then back to the electric heater completing the loop.
    A total of about 12' of hose.
    An in-block frost plug heater only heats the engine block.
    R
    Sleep with one eye open.

  15. #15
    Join Date
    Nov 2014
    Location
    Seattle, WA
    Posts
    2,827

    Default Re: Coolant circulating pump

    Quote Originally Posted by Ron Williamson View Post
    More like a coffeemaker than a plain thermosiphon.
    Mine is cut into the heater hose,and feeds toward the block.
    It comes out of the block and goes to the heater core in the cab,then back to the electric heater completing the loop.
    A total of about 12' of hose.
    An in-block frost plug heater only heats the engine block.
    R
    "More like a coffeemaker..." - a perfect description! Makes sense then. Still I have to say I like that forced flow heater with pump. I have hydronic heating on Skookum Maru. I could add one of those heater pumps and keep the whole boat heated over the winter without having to run the diesel furnace. Might not keep things really warm but I imagine that it would be enough to help with freezing and dampness issues.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •