Use propane radiant system with propane off?

[Jotel me this]

Just to keep the water/antifreeze flowing in the winter.. is it 'bad' to run my radiant system without the boiler heating the water?

I dont see how it could be 'bad' but just wondering.

Pipes are in cement, connected to pump and propane driver boiler. if i unplug the boiler and turn up the thermostat in the house, the pumps will run and move the water around.

Im wondering if doing this would help prevent the fluid from freezing in the pipes. the anitfreeze is only good down to around 30F and the purpose is to save propane seeing im using my wood stove.

 

[CaptSpiff]

Just to keep the water/antifreeze flowing in the winter.. is it 'bad' to run my radiant system without the boiler heating the water?
.......
I'm wondering if doing this would help prevent the fluid from freezing in the pipes. the anitfreeze is only good down to around 30F ......

So I've done this for a several day period until I had time to fix the boiler system. The circulators didn't seem to care. Same thinking, didn't want standing water in the pipes. I was more worried about my boiler's water jacket connection seals, but no leaks after 3 days.
Your statement about antifreeze/water mix only rated down to 30degF seems wrong. Are you sure that's the number?

 

[maple1]

Yes - antifreeze being good to only 30f is not much better than no antifreeze. Something seems a bit off there.

Also, I don't think a properly designed system would circulate water on a thermostat call if that water wasn't hot enough to provide any heating value. But that might be beside the point of the questions & irrelevant.

Yes, it would help - but is it necessary? Do the pipes pass through unheated spaces? Is the circulating you are doing circulating through the whole system or just the floor?

 

[Kiotick4010]

My control panel actually is set up, by the manufacturer, to run the circulation pumps for a few minutes every 24 hours.

Keeps the pumps from seizing.

 

[Jotel me this]

So I've done this for a several day period until I had time to fix the boiler system. The circulators didn't seem to care. Same thinking, didn't want standing water in the pipes. I was more worried about my boiler's water jacket connection seals, but no leaks after 3 days.
Your statement about antifreeze/water mix only rated down to 30degF seems wrong. Are you sure that's the number?

Yes - antifreeze being good to only 30f is not much better than no antifreeze. Something seems a bit off there.

Also, I don't think a properly designed system would circulate water on a thermostat call if that water wasn't hot enough to provide any heating value. But that might be beside the point of the questions & irrelevant.

Yes, it would help - but is it necessary? Do the pipes pass through unheated spaces? Is the circulating you are doing circulating through the whole system or just the floor?

Its due to the amount of antifreeze. The installer said he didnt want to add too much to the water because it puts a strain on the system and weakens seals. I have googled this and there does seem to be a correlation between too much antifreeze and failure of seals/pumps having to work harder

 

[CaptSpiff]

Its due to the amount of antifreeze. The installer said he didn't want to add too much to the water because it puts a strain on the system and weakens seals. I have googled this and there does seem to be a correlation between too much antifreeze and failure of seals/pumps having to work harder

Everything in life is a compromise:
(broken link removed to https://thayercorp.com/to-freeze-or-anti-freeze/)

 

[Wooden Head]

Its due to the amount of antifreeze. The installer said he didnt want to add too much to the water because it puts a strain on the system and weakens seals. I have googled this and there does seem to be a correlation between too much antifreeze and failure of seals/pumps having to work harder

I would change installers. That advice is pure Horse Pucky. Developing antifreeze for radiant/hydronic systems is what I did for a living.

 

[maple1]

Its due to the amount of antifreeze. The installer said he didnt want to add too much to the water because it puts a strain on the system and weakens seals. I have googled this and there does seem to be a correlation between too much antifreeze and failure of seals/pumps having to work harder

But if you only gain 2° of freeze protection, what is the point of adding any?

 

[Kiotick4010]

Read the link that captspiff provided.

Freeze point and burst point depend on antifreeze concentration. Negative thirty degrees is attainable with the right concentration, but you don’t want to go there , primarily because of the extra pumping power required to circulate the fluid.

Some people probably do use very low concentrations of antifreeze. They do this to take advantage of the anti corrosion additives in the propolyne glycol antifreeze formulation. In that case, the freeze protection from the antifreeze would be minimal.

Freeze protection requires higher concentration, but too strong of a concentration can be a bad thing.

Read the link.

 

[Wooden Head]

Read the link that captspiff provided.

Freeze point and burst point depend on antifreeze concentration. Negative thirty degrees is attainable with the right concentration, but you don’t want to go there , primarily because of the extra pumping power required to circulate the fluid.

Some people probably do use very low concentrations of antifreeze. They do this to take advantage of the anti corrosion additives in the propolyne glycol antifreeze formulation. In that case, the freeze protection from the antifreeze would be minimal.

Freeze protection requires higher concentration, but too strong of a concentration can be a bad thing.

Read the link.

I read the Link.
All due respect to the person that wrote it but, They only got about 30% of it correct.

 

[CaptSpiff]

I read the Link.
All due respect to the person that wrote it but, They only got about 30% of it correct.

OK then,.. don't keep it a secret,...what's your experience?

 

[Kiotick4010]

There’s a disclaimer in the last paragraph saying the info isn’t all inclusive.
I didn’t see any glaring errors in the document.

If you did, you should identify them rather than spouting a blanket dismissal.

But, whatever, it’s the internet, where everybody is an expert.

Just ask them.

 

[Wooden Head]

Read the above post for my experience.

 

[Wooden Head]

There’s a disclaimer in the last paragraph saying the info isn’t all inclusive.
I didn’t see any glaring errors in the document.

If you did, you should identify them rather than spouting a blanket dismissal.

But, whatever, it’s the internet, where everybody is an expert.

Just ask them.

If you want to have a better understanding look at DowFrost and their specs.

We can start with the wrong statements:
- Inhibited glycol reduces scaling. Just because it has what may be classified as an inhibitor, it may not inhibit scaling, What will? Distilled water
- Reduced heat transfer. Most concentrations are a heat transfer products.
- More difficult for air elimination. This is like saying, I wouldn't buy those tires because I would need to check the air pressure.
- System flushing and clean-up needs to be done before using. Again, why do I need to take the old oil out of the engine and change the oil filter when adding new oil?
- At freeze point fluid will not flow. Not so! At the temps between freeze point and burst point more ice crystal form as the temp drops. Each system will have a point where it can't move the slushy fluid.
- There are no corrosion properties in propylene glycol. That is why there is an inhibitor package added to it.

These are just the highlights.

 

[CaptSpiff]

- Inhibited glycol reduces scaling(???) Just because it has what may be classified as an inhibitor, it may not inhibit scaling, What will? Distilled water.

Using distilled water is the biggest "pain in the ***" of putting glycol in the hydronic system, but I agree it's near the top of the important list. My best learning moment about hard water came when I was boiling water in a glass carafe and it looked like it was snowing inside the carafe. My current hydronic system has a house water feed point which I always keep off. Lets me monitor for leaks and keep track of how much water I'm adding and thereby diluting my mix.

Here's another article, a bit more complete:
https://www.hpacmag.com/features/how-to-match-glycol-levels-to-various-systems/

 

[Kiotick4010]

Now we’re getting somewhere. Again, the article is an overview, not a masters thesis. I do have some background in cooling systems on engines in a professional situation. A good anti freeze will have an additive package that does indeed inhibit scaling. That additive package can’t overcome truly bad water, but it is part of the package manufacturers specify to control scaling in your engine and protect your water pum seals. A boiler system would have similar requirements.

Water has superior heat transfer characteristics compared to any antifreeze. Water is, in fact a heat transfer agent, just like antifreeze solutions, but water has a higher heat transfer coefficient than antifreeze solutions. The higher the antifreeze concentration, the worse the heat transfer coefficient.

Air elimination: don’t know, but if antifreeze increases the surface tension of the medium in question, water elimination through a common scoop valve would be potentially problematic.

Flushing is a common recommendation whenever any cooling /heating system fluid is changed . Not sure what your beef is on this one, either.

No fluid will flow below the freeze point. The antifreeze solution will most definitely flow at a temperature below 32 degrees, where water freezes. Not sure what your arguement is on this one.

Does anyone market pure proplyne glycol for radiant systems? I think not. They all have an additive package. I don’t think the link is suggesting use of pure glycol.

 

[Jotel me this]

But if you only gain 2° of freeze protection, what is the point of adding any?

Exactly. Just another "Lets take the customer's money" trick. I paid over $300 for the 20 gallon tub of glycol and im thinking i should call the company and complain.