The art of listening

I find that most customers may understand their own heating system far better than the people that put it in. If you pay attention to what they say, you are often led directly to the problem. This customer had a litany of things to reveal about the system. He talked about its operation in general  how much gas it used, how much noise it made, how the sunroom was never warm enough, how the dining room was always too hot, how the boiler room was always hotter than the hubs of hell, how the little red lights on the staging control were always on, how the damn snow didnt melt, how the relief valve on one of the boilers kept going off, and how there was something seriously wrong with the glycol. Hello  something wrong with the glycol? It is critical to keep asking questions to gain clarity. So I asked: What do you think is wrong with the glycol? The customer answered: It freezes. Freezes? How did the glycol freeze? (those damn questions again). The customer said I drained some glycol out of the boiler and put it in a jar and put it in the freezer. Why exactly did you do that? I asked. Well, because I smelled glycol in the boiler room after the relief valve went off last month and called my plumber and said: I might be losing glycol. He said, Well relief valves will blow from time to time& I will come around and check your glycol next week. He did and said it is just fine, nothing to worry about, but it didnt make sense to me, and he didnt seem too good with the glycol tester  it looked just like the kind you use for your car  and isnt heating glycol different? So I checked it myself... I thought about it for a moment. There was no easy way to break the news. I think your driveway is probably frozen, the tubing has probably burst here and there, and if so, you may have to jackhammer the slab up and re-do the whole thing next summer, says I. I hope that damn plumber is running hard! says he. I hoped so too. You can see what a powerful troubleshooting tool it is to just listen to the customer and ask the right questions  but what happened here, really? Lets figure it out.

Customer spells it out

I liked this customer, because he made it easy. He got tired of seeing a wet boiler room floor, so he put a five-gallon pail under the relief valve pipe. He told me the relief valve blew off about every half hour. After the relief valve goes, how much fluid is in the bucket?  says I. One point two gallons  exactly  every time, says he. A rough calculation established that there was approximately 40 U.S. gallons of fluid in his system. With the relief dumping out 1.2 gallons of fluid every half hour, he was feeding in 28.8 gallons of fresh water every day. You can be pretty certain that after a month of introducing 28.8 gallons of fresh water every day, there would be precious little glycol left. This story shows you how a very simple problem can cascade out of control with disastrous results. This system had three cast-iron boilers operated by a boiler reset staging control. The installer of the control didnt use the handy little tie strap that came with the control to firmly affix the controls boiler sensor to the high temperature boiler piping. No, he used black plastic electricians tape instead. When the tape got hot, it got soft enough to release the sensor, which dropped behind the boilers onto the floor  which was around 70?F. So now the boiler control thinks the boiler sensor is only 70?F, but its little software brain says it should be 160?F. Like it was programmed to do, the boiler control asked for every boiler to fire. The little red lights on the boiler control duly come on and the boilers duly fire up, but the control doesnt see any of this, it only sees that the boiler sensor is still at 70?F. The boilers heat up all the way to 200?F, where their high limits finally shut them off, then turn them on, then off, ad infinitum. The snowmelt system had a four-way mixing valve. The pump relay on the slab side had never been wired properly so the pump didnt run. When the mixing valve opened to let heat into the slab, nothing happened. So the valve opened wide because the snowmelt control was looking at a cold sensor too. When the valve was almost fully open, a slug of 200?F water made its way into the pipe holding the snow melt sensor  an equivalent sized slug of ice-water also made it into the boiler loop. The mixing valve immediately closed again. And the relief valve? The expansion tank was flooded. Every time the boilers ran the loop temperature up to 200?F the fluid expanded just enough to pop the relief, when the slug of cold water gushed into the boiler side, the boiler loop cooled off just long enough to open the boiler fill valve and bring the pressure back up  repeat every half hour, and the next summer you are jack-hammering up an 800 square foot concrete driveway so you can replace the snow-melt system. Yes, PEX pipe will burst if its frozen in concrete. Details folks, details!