Here is my problem that no one can seem to help me with. A while back(2 months) our water in the shower started getting lukewarm so we had to turn the faucet up to the hottest setting in order to take a shower. The water was comfortable but not extremely hot. This does not happen every time as maybe 85% of the time it is fine but the other 15% of the time it is lukewarm or a little hotter. We called or furnace technician and he "shocked" our hot water tank by draining it and refilling it with cold water. We have a storage tank for our Burnham oil fired boiler. We thought that worked but a few days later, the same symptoms again. We called our technician again and he checked it again. He said the only thing he could think of is that it is the thermostat in the hot water tank. He replaced it. That seemed to work fine but after a few days it was back to the same old problem. We called him back and he said he had no idea how to fix it and we should call a plumber. We are still living with it because most of the time our water is nice and hot. Now comes another problem. The water in our kitchen faucet will now only get lukewarm at best even after running it for a minute or so. what is going on? I would call a plumber but we are short on cash and I'm afraid the plumber will get here and will say that he doesn't have a clue. Any ideas?

how is the water in the other faucets when they are run alone and when they are run at the same time as the shower?

Sounds like your "tech" was not properly trained and used parts and components that were not necessary. A licensed plumber, just might be the answer to your semi-hot water, but an OEM specialist might be the better way to go.

Best Wishes

The heat exchanger coil could be getting dirty on the outside so it is not heating the water fast enough, although the fact that you have a storage tank should mitigate that problem, but it should also make the water consistently the same temperature so it is hard to diagnose with the little information we have.

The water is fine in the other faucets. The kitchen faucet just started to only get lukewarm a few days ago.

Possibly but he installed the furnace and hot water tank(16 years ago) and has been working on them for near 30 years yet I still think he should have known the answer. Could it possibly be the mixing valve for the shower? I have no idea about the kitchen sink.

Heat exchanger is fine.

if the shower cools down but the faucets do not then the problem is in the shower valve.

Do you have a thermostatic mixing valve on the outlet of the storage tank?

I have only 1 faucet that goes around.

I'm not sure. What would it look like?

A 3 pipe connection...Hot, Cold and Mix, with a knob to adjust the temp.

No, there is no external mixing valve. Now what?

Let's review.......the shower would intermittently only produce warm water. When this happened, every other fixture in the house was fine? Recently, the kitchen faucet has only been getting warm. Is it a single handle faucet? Is this now a constant problem? Is the problem with the shower, now constant?



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Correct. The water in the shower is still not the hottest but tolerant and the water in the sink is lukewarm at best. The water in the sink is hot but I think it was hotter but I think the technician turned it down. Not enough so that the water should be lukewarm anywhere.

Starting at the hot water tank.....map the connections to the hot water,,,1st, 2nd, 3rd..etc. Don't forget things like tempering valves on toilets. We'll look for a cross-connection. A valve that passes cold to hot in the closed position. The intermittent is strange, but I suppose an o-ring can roll out of a groove, but not every time the valve is used.