Arcoflame boiler/no hot shower problem
I just finished a bathroom project for a client with a big rainshower (legal) hansgrohe shower head, large walk-in shower, glass tile everywhere, elec. radiant heat in the floor, and a built-in storage cabinet. It was a major remodel and the final bill reflected that. The problem is that the shower never gets very hot, even though the sink faucet can deliver scalding hot water. In trying to suss out the problem, it sometimes seems like if one keeps the flow to the shower head to a minimum, very hot water can be achieved, but even this doesn’t to be the answer all the time. We took apart the Kohler thermostatic valve and set the “anti-scald” ring such that the shower should be getting the hottest water possible, but still the shower only gets to luke-warm temps. The client says that they had the same problem with the old bathtub — in that case, the bathtub filler would only produce luke warm water while the shower could produce very hot water. Which leads me to think its a flow rate issue… and therefore a problem with the boiler. I know nothing about boilers. I understand hot water heaters, but boilers…? The boiler is ancient. It’s made by American Standard, and it is an Arcoflame PH-2. The boiler is also used to heat the house (with baseboard radiators). Could the boiler have a maximum flow rate at high temps? What else could cause this problem? Any help would be much appreciated…
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Greetings Lynch,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again which will increase it's viewing.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
Peach full,
easy feelin'.
All on-demand water heaters have a limit in how much heat they can add at a given flow rate. There should be some number listed on the boiler or heat exchanger that shows what the limit is for that model. Modern tankless heaters give about four gallons per minute and some can go as high as 8 GPM.
If your shower set up is pulling 6 GPM, the water will probably never be hot. If the flow is more normal (~2.5 GPM) then you may have a clogged heat exchanger or some other problem that limits the heat output of the burners.
Oh. So boiler is like (or maybe "is") an on-demand hot water system?
It doesn't have a tank...? Now that I think of it, it's a big monster of a
system, but it doesn't look like it has a tank. If that's the case, then
this all makes sense!Thanks TJK.
If the boiler is used for heating as well as DHW, there is probably a heat exchanger buried somewhere in the system and some kind of bypass valve and control that lets it work in the Summer months when no hot water is needed in the floor loops.
Another problem comes to mind.
You say "old boiler" is the plumbing old as well?
what are the pipes made of?
If it's galvanized iron, hot water causes all kinds of problems one of which is calcium build up & scale. that will reduce the flow of the hot water.
“The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing.” —Albert Einstein
If cleaning the coil doesn't work, they could attach a boilermate hot water maker to their boiler.