Hi everyone. I am new to this forum and was hoping you guys can help me out. I recently bought a house that was built in ~2001. It has a hydroair system with 2 zones. The second zone contains an air handler in the attic. I live in New England so it is not ideal that they ran the hot water pipe up into the attic to the air handler. So to ensure the pipes don't freeze they had antifreeze in the system. I was sure the previous owners never had it flushed. So I had an HVAC/oil company come out and flush the system, remix an antifreeze solution, and pump it back into by system. I asked them what solution they used. He said they used a 50-50% mixture of antifreeze to water. I know they charged me for 10 gallons of glycol. That seemed like a lot to me. So I asked him how he came to that amount of antifreeze. He said he knew the boiler held ~17 gallons and then added that to what was he thought was in the piping.

So what I really need help on is how much water does my boiler really hold? It is a Peerless boiler with a model number of WBV-03-110-WPC. It was built ~2000. I wrote to Peerless earlier and asked them. From what I can find on their website it looks like the WBV-03 only holds about 11 gallons. If this is the case there is way too much antifreeze in the system and I will be calling the oil company back and complaining!!!!

Thanks for you help.

 

A system that is designed to hold glycol will have a plastic tank and a pump for make up water.
What it sounds like is that you have a typical system connected to domestic water for water make up.
In your system they would need to have a pump to fill the system and then when full, open the valve to domestic water for make up.

Is this what you have?

It won't make too much difference however in that you need to fill the system until it is 100% full.
They could have been wrong in their estimate of the boiler capacity but it doesn't matter because they will be filling the pipes as well as the boiler to give you a 100% fill.

They installed inhibited propylene glycol, right?

 

Rather than worry about if you have a 50/50 mix or some other percentage I suggest that you invest $50. in a refractometer and test the concentration yourself.

Robinair 75240 Coolant and Battery Refractometer

You can use this for the antifreeze in your cars also.

Also note that when you use antifreeze in a heating system you must do a periodic test for corrosion inhibitor and pH level.

 

You need to calculate the amount of piping and how much the hydro-coil will hold.
Here is a link to calculate pipe volume.
btu_pipe
The coil volume you need to get from the manufacturer of the coil. If you exceed 50% you may need to increase pump and maybe expansion tank size.

 

Gregg H,
What you explained is exactly what I have. By "inhibited propylene glycol" you mean the non-toxic antifreeze, right. What they used was non-toxic propylene glycol. It has the redish tint.

Furd,
I thought about buying a refractometer myself. But I am not an HVAC guy. I also talked to someone I know today that said I need to check for the PH level. I was told that I want the pipes freeze protected to around 10 degrees, which would be burst protected to about 10 below. Does this sound right?

Thanks for all your help. I am not an HVAC guy, but just a homeowner trying to not get screwed. So I would rather not go out and start buying all the equipment the people you hire should have!!

 

I've been retired for four and a half years now, I have a forced air furnace and I bought my own refractometer just last year so I would have a means of testing the antifreeze and battery in my car.

I personally would not think my pipes were "burst protected" at any temperature below what the freeze point of the antifreeze mixture was. While it is true that an antifreeze mixture will get "slushy" before it freezes hard it will start to expand before that hard freeze point is reached.

My personal "happy zone" in regards to pH would be more than 8 but no more than 11. The corrosion inhibitor will be specific to the antifreeze manufacturer but is most likely a molydate based or nitrite based (or combination of both) compound and you should be able to get a test kit from the manufacturer. Or you could trust the people that put the antifreeze in the system for you to test it at least yearly. I would rather have my own testing equipment and schedule but it does require a small outlay of money.

When I was supervising commercial/industrial sized heating systems I had a reputable chemical company supplying chemicals but we did our own testing. We also had systems that were originally filled with antifreeze mixtures and I had the antifreeze removed and used water with corrosion inhibitors only. My argument against antifreeze included the fact that if we had to worry about the system freezing we had far more to worry about then just freezing. Of course in my area temperatures below freezing are not common and rarely last for more than a week or so.

 

if you really want to feel good about freeze points of your mixture simply put some of the mixture in your freeze at about five below. you will now get to see what the mixture would be like if it gets that cold inside your pipes. it will ease your mind .

 

When the old antifreeze was drained from the system was the system then cleaned and flushed before the new antifreeze was injected? Antifreeze that's not well maintained tends to get funky over time so it's best to be sure all of the old stuff is out before putting in new.

Unless you live in Alaska you don't need a 50/50 mix, 35% is sufficient. That will give freeze protection to just about 0º and burst protection to about -40º. The advise to purchase your own test equipment is sound, it'll give you peace of mind. A refractometer and ph tester will not break the bank.

High concentrations of antifreeze reduce the system efficiency and leaks and corrosion will eventually start showing up in pipe joints, valve packing, etc.