Heatmaker II winterization

JZZH

Hi, I have a Heatmaker furnace HW-M2-100LP (https://www.heatmaker.com/v/vspfiles/images/pdfs/HSeriesManual.pdf) in a cottage. In the past it was keeping the cottage heated to 50F through the winter but I'm trying to shut it down this winter after winterizing the place.
Here are are what I did:
1. use air to blow water out of cold and hot outlets (kitchen faucet, bathroom sink faucet, shower faucet, toilet tank)
2. fill the pipes with antifreeze till it comes out of those outlets
The air/antifreeze were injected from the main water inlet of the cottage.
The furnace has a 20 gallon tank and little water was driven out by air in step 1 and I only used up about 8 gallon antifreeze in step 2, so I take it that neither step affected the water tank much.
This is my first time doing winterization so pardon my ignorance. While I was on site, this tank issue did not occur to me and I did not open up the enclosure of the furnace to look for a drain port (I did not seem to see one outside). Before I go up there again, I'd like to ask the experts here if the tank should have a drain port besides the normal water inlet/outlet. I did not see one in the manual either.
Or, is it that the tank is actually *not* holding the hot water (for domestic use) - rather it is for holding the glycol heating fluid? After reading the manual again, I seem to be inclined to the latter, and that would explain the little amount of water blown out in step 1 and not much antifreeze used in step 2. Figure 1 of the manual seems to match that assumption.

Another question that I have is about the pipe around the backflow prevention value and auto-fill valve (see parts 11 and 4 in Figure 16). I am not sure if the pressure in step 1 and 2 was strong enough to drive the "boiler feed water" in that section of the pipe into the heating fluid (glycol) line that goes to the baseboards; in particular, now I am not sure if I did it with the value 10 closed or open :-( I am concerned that if there is still water in that section of the pipe would it freeze and burst the pipes and valves. How normally and properly is that done?

EdTheHeaterMan

There is another procedure needed to fill the Hydronic section of the system. It sounds like you only loaded Antifreeze into the Domestic water portion of the house.

To be clear, the water that flows thru the radiators is not connected to the water that goes into the shower, outdoor hose connections, and kitchen faucets.

To better understand the system you have an open system that has the water you drink, cook with, and take a shower with. Open means that once you "OPEN" a tap the water leaves the system and goes on the ground or down the drain pipe.

The Closed system recirculates the same water thru the radiators to release the heat, then it returns to the boiler to be heated and sent out to the radiators again.

Trianco Heatmaker did something a little different by making the tank part of the closed system. The Domestic Hot Water (DHW) is heated by a heat exchanger coil that is submerged in the "closed system" tank. Cold Domestic water enters the coil and is heated on demand as the water flows thru the coil that is submerged in the hot tank of "closed system" water. BUT... the two different water systems only connect at the Fill Valve on the boiler piping system and that should have a Back-flow prevernter check valve so that water never backs up into the domestic water system. You don't want to during that stuff..

You need to remove some of the closed system water and install "boiler Antifreeze" that is approved for that boiler. that antifreeze can be permanent. It can stay in the closed hydronic system indefinitely. Yu will need to do that before the baseboard radiators freeze up and split, the boiler heat exchanger will also freeze and fail

EdTheHeaterMan

Most plumbers will remove all the water in the domestic pipes with air pressure. With no water, there will be no frozen pipes.

The antifreeze is put into the Hydronic system so you don't need to drain the pipes every year. Just test the specific gravity to see the freezing temperature is below the expected low temperature. Similar to the test on the coolant system on an automobile.

JZZH

Hi Ed, thanks for your comments and answers.

Yes the hydronic system has always been filled with boiler antifreeze (cryo-tek) not just regular water (and I added some this year as well), so that part is fine. I was just trying to winterize the domestic water part - I used air and (food grade glycol) antifreeze to be double sure as there are always people saying that air won't get some trapped water out.

So, I initially thought the tank was holding domestic water and was wondering if there would still be 20 gallon regular water there (that would be a big problem). Now you have confirmed that the tank actually holds boiler antifreeze - that's a big relief.

Indeed I don't want to mess with the Fill valve part, but I do wonder if there is still regular water trapped in that section of the pipe - would that freeze and burst the pipe?

EdTheHeaterMan

Interesting. question. The small section of pipe from the potable (Domestic) water system to the boiler water may be filled with water that contains no antifreeze. Never addressed that issue but I only did about 3 winterizations in my customer base. I always referred that job to a plumber for liability reasons. Did not want the aggravation of filling up a house in the spring and finding the broken pipe.

Maybe other contributors on this site have more experience.