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?

I maintain several residential buildings and in one of the buildings in the last several months have been getting complaints of the water not being hot enough at all different times of the day or week. In this bldg there are 13 apartments with a laundry room with 2 washers. About the same time as the complaints came in, we converted over to natural gas from LP but just coincidence in my opinion. We have 2 stage Lochinvar boilers with a Weil Maclain 100 indirect 75 gallon storage tank. There is a hot water recirculation closed loop that I just put a new circulator on that I thought would help as the other pump was bad but it didn't. We have a Tekmar 262 set up for DHW priority using a pump not valve and I haved checked all apartments for leaks. I adjusted the DHW exchange to 165 from a setting of 140 which just couldn't heat the water fast enough and I'm not sure what to set this at. The problem with setting it higher is that the building bakes because of the overriding of the target temperature being raised to meet the continuous demand for hot water therefore pushing that hot water for heat through the building when the reset curve may only be calling for 145 degree water because it is 40 outside of something. In the other 5 buildings on the complex, during "traditionally" low hot water demand times during the day, there is not a lot of demand for hot water as evidenced by no indicator on the Tekmar's and no pumps running. Most people work during the day and this makes sense. Maybe half of the apartments are occupied in this particular problem building. So the obvious question would be is the tank too small? Didn't appear to be several months ago and not too much has changed. Should the DHW exchange be raised to 180 with the risk of baking the tenants as 165 is already doing? These boilers have a main circulator running all the time except for the priority kicking or WWSD. And it is in an open loop set up where to me blurs the distinction between supply and return. It is one loop and separate pumps pull off this loop into the boilers and then return right back to the main loop. So technically, where do you put the supply sensor for the Tekmar. It was set up on the large loop but it never got satisfied as far a target temperature was concerned. I just placed it right off the supply on one of the boilers to get a more accurate supply temperature and as not to bake the building as much. In fact, all of the sensors in the other buildings are on the return side which to me is wrong and is also in the Tekmar booklet it stated on the supply it goes??? Go figure. All installed wrong in my opinion. And wired wrong too. Would appreciate any feedback as the tenants are not happy. Thanks, Jim