Heating boiler antifreeze types, installation, questions & answers.

This article series describes how to add anti-freeze to a heating boiler and to the hot water or hydronic heating system piping, baseboards, convectors, radiators, etc. to protect the system from freeze damage.

Q&A on How & Why do You Add Antifreeze to a Boiler?

These heating boiler antifreeze questions & answers were posted originally

at ANTIFREEZE for BOILERS - be sure to review that information.

Lowering heat transfer will also lead to lower heat loses when there is no call for heat.

There is a thermostat inside boiler that turns on boiler burners by water temperature inside the boiler, not just by call for heat.

When temperature drops beyond the certain level (it depends on boiler settings) AND there is a call for heat, burners will start. Burners will stop when boiler temperature will reach the settings.

Therefore, lowering wetting action by adding antifreeze will just delay heat transfer.

It will cause longer times to release the heat from water and from the boiler, not to burn more gas or oil. In other words, boiler will keep its water temperature longer.

There is some heat loss during journey of hot water to radiators though. It means that extra energy will only be used for

(1) additional time to run the circulation pumps (which is minimal in residential heating) and

(2) on extra heat losses during water journey via pipes to heat exchangers (like radiators etc).

On the other hand lowering heat transfer will also lead to lower heat loses when no call for heat. On 2018-10-13 by Vlad - l

by (mod) - Lowering heat transfer rate from heating pipes to the occupied space will always increase the system heating cost.

Vlad

You're right;

The aquastat control turns on the oil or gas burner based on boiler temperature (and a few sophistications on that)

while
the thermostat, on a call for heat, in most installations, simply turns on the circulator pump to cause hot water to circulate through the various heating zones.

An exception is in some countries such as Canada where custom is to wire the circulator to run continuously during winter weather; in that case (giving more even heat and improved freeze-proofing), the thermostat will turn the burner on and off.

The "heat loss" that you cite is not necessarily undesirable, depending on where those heating pipes are routed, as they may be delivering heat to areas where it's actually needed, for example to avoid frozen pipes or to keep a crawl area dry.

Lowering heat transfer rate from heating pipes to the occupied space will always increase the system operating cost.

Does antifreeze in a hot water boiler have to be added on a regular repeated basis,\?

Does antifreeze in a hot water boiler have to be added on a regular repeated basis, in other words boosted every 2 or 3 years? AUTHOR:Bob (no email)

by (mod) - no

NO, Bob, if you are having to add antifreeze I suspect there is a leak somewhere.

A hot water heating boiler leak that causes water to have to be added to the system will dilute its antifreeze concentration. And of course none of this pertains to steam boilers.

 

I'm Looking for an alternative to Anti-Freeze in my Heating System

Looking for an alternative to Anti-Freeze. Wife (who claims she's much smarter than I) keeps the house cold on winter days (64) and cranks it down to 56 at night.

We've argued about cranking the heat up on the really bitter cold days (less than 10 degrees) because some of the piping runs up the outside walls to the 2nd floor but she won't give in.

I came up with an idea to throw a bypass timer on the circulator pump for that upstairs zone to just turn the pump on for let's say 5 minutes per hour.

I'm thinking that by occasionally circulating room temp water through the pipes at a regular interval, it would prevent the pipes from freezing.

Any thoughts on whether this might be a viable alternative or am I just spinning my wheels? On 2016-12-18 by John Wilson -

by (mod) - how to prevent house from freezing

John,

Some tips are found by searching InspectApedia.com for WINTERIZE HOUSE HEAT ON - using the search box just above.

Also see

• FREEZE-PROOF PIPES
• WINTERIZE - HEAT OFF PROCEDURE
• WINTERIZE - HEAT ON PROCEDURE

What should we do if boiler antifreeze is leaking into our drinking water?

Antifreeze is leaking into our drinking water. What can be done about it? On 2016-05-03 by Anonymous

by (mod) - stop using it immediately

Stop using the water immediately as you may be drinking poison.

Replace the leaking tankless coil used on your boiler to make ot water for washing.

Or

If your boiler has no tankless coil it's probably missing a backlog preventer valve.

 

How do I know if propylene glycol is leaking into the drinking water?

How can you tell if the propylene glycol is leaking into the drinking water? What are the signs? Can it be seen, tasted or smelled? On 2015-09-03 by AJ

Reply by (mod) -

AJ

For space and citations I've moved your question and given a detailed reply at

PROPYLENE GLYCOL DETECTION & POISONING SYMPTOMS

Post a question there if you need more information

 

I discovered antifreeze in our drinking water

I also discovered antifreeze in the drinking water (luckily non-toxic antifreeze was used).

I don't have a tankless heater, but I do have a Boiler Mate water heater incombination with a Well Mclain boiler.

Is the water heater the only location where antifreeze could mix with fresh water, or are there other possibilities in the boiler itself. On 2017-10-14 by Anonymous

Reply by mod:

If boiler antifreeze leaked into your water heater from the heating boiler, then anywhere that water out from that water heater traveled needs to be flushed clean. It would make sense to flush both hot and cold water supply pipes in the building and then to test your drinking water to be sure its safe.

Can't I use of the Propylend Glycol that is put in RV's,Cabin systems,etc. (Uni-Gard-50) sold in Home Depot?

Why can't Propylend Glycol that is put in RV's,C abin systems,etc. (Uni-Gard-50) sold in Home Depot, be used in the Hot Water system of a home? Nov 16, 2012) Ron

Reply:

Ron,

In the article ANTIFREEZE for BOILERS that is exactly what experts recommended.

I see an oily look in boiler water after installing antifreeze

My plumber recently drained my Weil McLain Boiler & I have a Sid Harvery McDonnell & Miller cut-off. He put in what I believe is anti-freeze the water color is a light green & when I drain the water its slightly oily looking. I need to know if this is toxic since I toss the water outside into the ground.

Also is this the right anti freeze to use? THe plumber will not return calls & will not speak to me of what he did. (Jan 23, 2014) Marni Olsen

Reply:

Marni, there are two different types of antifreeze used in heating systems, one toxic and the other using food-grade products is non-toxic. You will need to ask the installer what product was used.

Installers may use either propylene glycol (non-toxic food-grade antifreeze, recommended where a tankless coil is used on a heating boiler and in some other cases), or ethylene glycol (automotive type and highly toxic antifreeze).

Leave a polite message for your plumber noting that you just want to know the brand and product of antifreeze installed.

About your comment "when I drain the water" - I'm unclear why you would ever be draining water from your heating system - that's not a normal step except for steam boilers which surely is not your case. What's going on ?

Let us know what you are told and I can comment further.

 

What other uses are there for boiler glycol

What other uses are there for boiler glycol. I just changed boilers and have about 15 gallons left over (Oct 5, 2014) Fred

Reply:

Food grade antifreeze products are also used in winterizing RVs and plumbing.

 

How do I turn on the circulator pumps without the heat on?

I have the right antifreeze, pump and hoses. I connected them as described, the problem is without the furnace turned on the circulator pumps do not turn on therefore blocking the transfer through the lines, the antifreeze only goes through the boiler.

How do I turn on the circulator pumps without the heat on? they only turn on when the temperature gets above a certain level and the thermostat is up demanding heat. I can't find anything that addresses this question.
Thank you, Ed Roy (Nov 22, 2014) Ed Roy

Reply:

Ed you may need help from your heating service tech to turn on the circulator pumps or open zone valves - that can be done regardless of whether or not the boiler's burner runs.

Typically if power is on to the circulators it is also on to the boiler because they're usually powered off of the same electrical circuit.

But it's trivial to disconnect the power to the oil burner or gas burner, leaving it off while allowing the circulators to run either by calling for heat at the thermostat(s) or by jumping the thermostat terminals at the circulator relay.

 

Do Need to add antifreeze after minor plumbing work?

I replaced a relief valve on the boiler, losing about a gallon of boiler water in the process. I added that water back. Do I need to add more antifreeze?

Reply:

Probably not - unless the total volume of your heating system is very small the reduction in freeze protection is likely to be slight.

 

After adding antifreeze as a winterizing of the heating system, can I leave with the temperature set belo 55 degrees?

After you have winterized your system , does that allow you to leave for an extended vacation with the temp.set at lower than the 55 degrees f. that I set it at now. 29 April 2015 Ron said:

Reply:

Ron:

The purpose of winterizing is to prevent freeze damage to building plumbing & other systems.

But there are choices to make between "heat on" and "heat off" winterizing methods. And the decision about the safest "low" setting of the thermostat depends on the particular home and what other winterizing steps were taken.

If heat is to be left ON in a partially winterized building see the procedure

at: WINTERIZE - HEAT ON PROCEDURE

If heat is to be turned OFF and the building completely winterized, see the procedure

at: WINTERIZE - HEAT OFF PROCEDURE

The temperature at which you can safely leave your heating system varies depending on many factors:

- the house insulation level or rate of heat loss

- the routing of or location of pipes that may be exposed to cold spots

- whether or not you've placed antifreeze in the heating pipes

Details are in the two articles I cited above. Don't hesitate to ask if after reading those you still have questions.

 

Where do I go to buy boiler antifreeze?

Where can I buy 60 gal of glycol? On 2016-05-14 by George marty

Reply by (mod) -

Check with your HVAC or plumbing suppliers

...

...

Continue reading at ANTIFREEZE for BOILERS - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• ANTIFREEZE for BOILERS
• BACKFLOW PREVENTER VALVE, HEATING SYS - protect building occupants from toxic boiler wate
• CHEMICAL TREATMENTS, BOILER for a discussion of the types of boiler treatments available, how & why they are used
• PUMPS, PONY PUMPS
• PROPYLENE GLYCOL DETECTION & POISONING SYMPTOMS
• RADIATORS for ROOM HEAT - home
• RADIATOR VOLUME & BTUs
• WINTERIZE A BUILDING - home
  • ARTESIAN WELL FREEZE PROTECTION
  • CHEMICAL TOILET FREEZE PROTECTION
  • DE-WINTERIZE a BUILDING
  • WATER TANK & PUMP DRAIN & WINTERIZE
  • WINTERIZE - HEAT OFF PROCEDURE
  • WINTERIZING an RV or MOBILE HOME
  • WINTERIZE - HEAT ON PROCEDURE

Suggested citation for this web page

ANTIFREEZE for BOILERS FAQs at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to HEATING BOILERS

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