Triple aquastat relay replacement question

Old 03-11-10, 10:43 AM
Thread Starter
Join Date: Mar 2010
Posts: 1
Upvotes: 0
Received 0 Upvotes on 0 Posts
Triple aquastat relay replacement question

I got this story second hand from my wife, so between my limited knowledge and her non existent knowledge, this is going to be a mess. Bear with me.

I have a really old gas Boiler (GM Delco) in my house. Not the most efficient beast, but it does the job without much complaint. A few weeks ago, I had something making a god awful racket down there, and the wife called someone over to take a look at it. I thought it was perhaps the circ pump, but apparently it wasn't. She didnt remember what he called it, just said he took something apart, greased or oiled it, and it stopped making the noise.

At any rate, after he did that, the kind old fella told her that we had, in her words "a 3 something switch, and we could replace it with a single and save a lot on our gas bill". I was down in our basement yesterday, and came across a cover mentioning a "triple aquastat relay". I'm assuming this is what he was talking about replacing.

So first thing, how much does something like this cost to replace? Why would I have a triple relay if I only needed a single? And would replacing it really save me money?
Old 03-11-10, 04:16 PM
NJT's Avatar
NJT is offline
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
Hi Mad, welcome to the forum!

I can't imagine what, other than the circulator, could the fella have taken apart and greased or oiled... that 'god awful racket' sure sounds like it was a broken pump coupler to me... can you find the repair ticket for the job? It shoulda been written down what he worked on...

So first thing, how much does something like this cost to replace? Why would I have a triple relay if I only needed a single? And would replacing it really save me money?
If you are reasonably handy, and able to change a light switch or electric outlet, you should have no trouble changing an aquastat yourself... you can purchase aquastats on the internet for around $150, probably less than half what a repair man will charge.

A 'triple' aquastat is used when the boiler system contains an internal coil for the purpose of making domestic hot water. It sounds as though yours is not serving that purpose, but it's possible that at one time it could have been. Is there a big round or square plate on the boiler with a bunch of bolts on it and two pipes cut off sticking out of it?

The triple aquastat would work to keep the boiler warm/hot in order to heat the domestic water on demand.

One thing to caution against, and with your older system it is probably not as big an issue, is that some boilers that have spent their lives as 'warm start' systems with a triple aquastat will begin to 'weep' (leak) water when they are allowed to cool. This is because the cast iron shrinks, and the gaskets/nipples etc can't expand to fill the gaps between the sections. This doesn't always happen... but it's something to keep in mind.

Will it save fuel? Yes, absolutely... mostly in the summertime... but I bet you shut the boiler off in the summer, yes?

So, let us know how the domestic hot water is made in your home, and if it appears that at one time the boiler took care of this... you can post pics for us to look at if you are unsure... set up a free account at Image hosting, free photo sharing & video sharing at Photobucket and upload the pics there, come back here and drop a link to your album. We'll take a look-see and let ya know what we think.

Thread Tools
Search this Thread
Ask a Question
Question Title:
Your question will be posted in: