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Heatmaker HW-M2-100

BoattailBu Member Posts: 12
Hello all, this is my first post so let me say I did do a search first and didn't find what I needed so I hope someone can figure this out.
Got a call to do a cleaning on this Heatmaker boiler on Friday. I show up and it turns into a no heat call as the boiler won't even fire.
Ended up replacing the differential pressure switch for the primary circulator and the Taco circulator for the system loop. Every thing was fine when I left.
The one thing that irritated me was that the homeowner said they never lost hot water, just heat which doesn't make sense to me because the pressure switch shouldn't have allowed the boiler to fire.
And just my luck, I'm on call this week so by 8:30 Saturday night, I get the call that they have no hot water.
I head over and realize, they have no heat either, it's just that they're half in the bag and haven't realized it yet.
Now the boiler fires, and immediately shuts off Boiler gauge reads 180*, both zones calling but the unit won't turn the Taco circulator on.
The primary pump works as I have continuity through pressure switch when boiler is on.
I called another tech and after much back and forth, we come up with the fact that it might have a thermostat in it.
I checked Google for some pictures and there is supposed to be a thermostatic union in here but for the life of me, I don't see it. I printed out the manual this morning and where it shows it, I'm nearly positive this boiler doesn't have it.

The question is, could it be mounted anywhere else and is it just bad luck that it failed after I was there or did I do something to kill it?

Also, if the t-stat isn't the problem, then I'm really at a loss as to what the problem is.

Thanks in advance.


  • BoattailBu
    BoattailBu Member Posts: 12
    Oh, and I forgot to mention the "howling" sound the combustion chamber makes on start up. From what the homeowner says, that's been going on all season but it isn't my highest priority right now. :/
  • icesailor
    icesailor Member Posts: 7,265
    edited February 2015
    Is this what you have?


    Heatmaker ll's are a strange breed. If they have the tank, the tank is the boiler water source. The DHW coil is put inside the tank to keep it from overheating and to make boiler water hot. The reason you got hot water after the boiler shut off on safety is because the tank was hot. It was still providing heat for the hot water. They're not that bad to work on if you understand them. Parts are another matter. Especially the thermostat. That controls the primary pump that pumps DHW through the coil in the tank. Like I said, they are a strange breed. That primary pump MUST run every time the burner wants to come on. Or else, the coil flashes to steam and makes snapping noises.

    A true Combi Boiler that worked.

    If it is a early 1990's vintage, the roaring can be a sign that the inside exhaust pipe has rotted out above the boiler flue outlet. Where it will recirculate exhaust with the incoming fresh combustion air and throw the A/F ratio in a hand basket on the way to Hell. If the exhaust has extremely high CO, it is gone. The inside pipe was Plexco or Ultra-Vent that should have been replaced with Stainless Steel. There are no replacement kits available. I have replaced the inner pipe but it was a project, time consuming, and not worth it unless there are "reasons".

    The thing mat be well beyond 20 years old. It may be time. If you scrap it, be sure to get the copper coil out of the tank. There's a lot of copper in that coil.

    Hope that's what you have and this is helpful. They really were nice. People were very happy with them. Its just that if the boiler tank went, the whole thing was gone. Useless. The only people that have parts are people that work on them and scavenge parts off of old ones they remove.
  • BoattailBu
    BoattailBu Member Posts: 12
    Not exactly sure of the age but the homeowner claims it's been 11 years since it had any service so it's that old at least.

    Thanks for the suggestion. The more I research, the more I think no hot water is the least of her problems and the howling noise might take precedence.
  • Zman
    Zman Member Posts: 7,446
    Heat maker was bought by Laars. They rebranded it as "endurance".
    If I recall correctly the thermastic valve is basically an automotive one that originally sat in the union on the top of the boiler. I can remember if it was the supply or return.
    These are one of the scarier boilers around. The flash to steam that ice mentions is real and dangerous.
    If the valve is missing, the vent has probably been condensing and rotting.
    The controls and wiring harnesses are really glitchy.
    Parts are hard to find and expensive.
    It might be time to look for a new boiler.
    Proceed with caution.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • icesailor
    icesailor Member Posts: 7,265
    Tracing the wiring is really a witch. They are all color coded and held together with cable ties. Difficult to use a Tick Tracer on or an amp clamp.

    If it looks like the one in the PDF, its a Heatmaker ll.

    They haven't had it serviced in 11 years? Do they drive their cars for 11 years without service? Checking the tires? Oil? How many oil changes or tire replacements in 11 years? I always had to replace the tires on my work vans by 40,000 miles or earlier.
  • BoattailBu
    BoattailBu Member Posts: 12
    It is a Heatmaker II. This is the only one I ever worked on. The only other one I saw was leaking from every possible location and I immediately condemned it even though the owner said it still ran.

    And I know what you mean ice about service but if people did what they were supposed to do, what would we do for a living ;)
  • icesailor
    icesailor Member Posts: 7,265
    That's true, but when they finally call you and it's a Ford (Found On Road, Dead), they can't believe it when you tell them that it is hopelessly dead. No resurrecting it. You have spent all kinds of time diagnosing something that belongs at the morgue or the Smithsonian, and they want a price to change it. You spend hours doing a proper work up and price, and they take your price around to show everyone. Including the one that says that he will do it for $100. less than the lowest bid.

    Sometimes, they have the decency to tell you that they got someone to do it for $500 less.

    And they don't want to pay you for your time diagnosing the problem and possibly fixing it.

    That's when you should realize that you might be better off working for Omar the Rapper, for $200. per week on commission sales and all the customers in the world to rape.
  • GW
    GW Member Posts: 4,605
    I really don't wish to add more pain to your story. We stopped servicing these old goats a year or two ago. Here's another twist, with our smaller staff we flatly tell new customers we don't offer 24/7 for systems we haven't installed (and service annually).

    Do these people by propane from your co?

    I sense something is wrong here, and it's not you.

    I'd be happy to share more thoughts, yet the average Web trolley may take my words the wrong way.

    Let me know if you'd like to converse more.

    Gary Wilson
    Wilson Services, Inc
    Northampton, MA
    [email protected]
  • BoattailBu
    BoattailBu Member Posts: 12
    Thanks guys. I'm just a tech. And a fairly new one at that. I had to call in the service manager to get things sorted out the first time I was there and the homeowner was into that repair for a fair amount. Now they're without heat or hot water and I have to let them know this thing might need to be replaced due to the cost of repair of the howling noise.

    I did prepare her for that today but I'm not sure she understands.
  • kcopp
    kcopp Member Posts: 4,188
    You can still get parts here... www.heatmaker.com
  • BoattailBu
    BoattailBu Member Posts: 12
    Got the issue resolved today. Primary loop pump, even though it was still physically moving(I have the little keychain tool from Grundfos) it wasn't apparently moving enough.

    Support from Laars was good I must say. But he said this model was out of production since before they bought Trianco which was 1998 so this boiler is minimally 17 years old.

    Homeowner is a little confused about some things but claims it was only 11 years ago that it was installed. If they are right, then I suspect some contractor pawned this off on an unsuspecting customer.

    In any event, a new primary loop pump got the heat and hot water back so she's happy but I did suggest she start thinking about a replacement due to the cost and (un)availability of parts.

    It still has a little "howl" on startup which Laars suggest is likely a dirty combustion chamber but no way was I going to tear this thing apart after I just got it running again. :*:)
  • icesailor
    icesailor Member Posts: 7,265
    edited February 2015
    The explanation was there. When the call comes, the primary pump starts, pumping water through the boiler part above the tank, and through the indirect coil. It isn't supposed to run if that pump isn't running. There is a pressure switch. Make sure that it is working. It should open with under 10# of pressure. Look on the instructions I sent you. I thought there was a flow switch on it too.

    It very well might have been installed by some slug as a new or reconditioned unit. The customer may have a failing memory too.

    Are you in Maine? Maybe it came from those guys on DownEast Dickering.
  • tim smith
    tim smith Member Posts: 2,544
    edited February 2015
    Its almost always a dirty combustion chamber causing the howl, but sometimes it could be a corroded burner head or low water flow. It is scary to me how many heatmaker parts are still on our shelf. We never sold one unit but serviced many. Once you are use to them they don't run too bad. You have to be careful on the tank circ pump when replacing as the tank runs up to 220 and a lot of circulators will go out on thermal overload. The potable water goes through a fin coil in the tank. Just fyi. I think I have enough parts to completely rebuild 2 of those except for tank and heat x. Good luck.
  • clavodulce16
    clavodulce16 Member Posts: 1
    Hello all,
    I also have this boiler and is just driving me crazy. I'm not tech but just a owner looking for help. I have the HW-M2-130; the last few wknd when the temp dips below the 20's the boiler seen to stop heating up the baseboards. How ever i do have hot water and boiler pressure shows 12-15PSI with temp at 160-180.
    I notice this happens only when the temp dips and is time to heat up the apt in the morning. for some weird reason it has always fallen on a saturday. HELP!!!!!!
  • kcopp
    kcopp Member Posts: 4,188
    It may not be the boilers fault.
    It may be that there is not enough baseboard/ radiation, that the home is poorly insulated or both....