Luke warm Hot water from tankless Steam system!!!

Unknown

setting is too low for the coil . No problem when the boiler is steaming - that's 200 + degree boiler water surrounding the coil . But 130 will drop the boiler temp too fast for even a quick shower .

We typically set the aquastat to 160 - 170 and mix the outgoing temp to 120 - 130 . Do you have some type of mixing valve on the coil ?

John Couture

Luke warm Hot water from tankless Steam system!!!

I have just purchased a 1910 era house that came equipped with a recently replaced oil fired Steam heating system (Replaced within last 5 years). The hot water is produced from the same system. The issue we are having is that the hot water is VERY sporadic, either scaldingly HOT or luke warm! i have been observing the system over many cycles to try and pinpoint when each is occuring, and it seems that the water is HOT when there is a call for heat, but if there has not been a call for heat in a few hours, the hot water temperature will drop to luke warm.
This leads me to believe that there is a problem with the aquastat, but i am not positive. Aquastat model is a Honeywell type L4006A. It is currently set at 130 deg. and the offset is set to 10 deg. Im not sure if these settings are correct either. Any help or insight will be greatly appreciated!! Thanks! -John

John Couture

AuquaStat

Thanks for the reply!! Yes, there is a mixing Valve on the hot water output, it is currently set at maximum (145 deg). When i bought the property a few months ago, the aquastat was actually set at 190 deg and we have been having the same issue. i had my boiler guy come and offer suggestions and he was the one who recommended i turn down the temp on the aquastat. Regardless, at the 190 or 130 setting, we still have the same problem

Leo

Do you have

You you have an automatic water feeder? If you do they keep a minimum amount of water in the boiler. You need to have the water level approx 3/4 of the way up the gauge glass in order for it (the water) to cover the coil. Don't go higher or out of sight because that will cause water hammer.

Leo

John Couture

water hammer?

Hi Leo, no i dont have an automatic water unit. I DO however keep an eye on the water level and make sure it is always at the 3/4 mark. What is water hammer? Does that effect the temperature of the hot water?

Leo

Water hammer is

Water hammer is steam hitting water in the pipes. It can hammer loud enough that you think someone is in the basement hammering on the pipes. If the system is overfilled water can get into the pipes, water can get into the pipes for other reasons but that doesn't seem to be your problem at the moment. I would keep the aquastat at 180. If the coil is getting older it can get covered with junk and not pick up the heat as it once did. Your problem isn't uncommon on an older steam boiler. My system does it on occasion also and a system I used to own did it too. I'm not only in the field I own a steam system. Do you have a lot of minerals in your water, if on a well it can be tough. Public systems can act up too. The aquastat has a probe that sits in a well, the well sits in the boiler water. If junk builds up on the well it can act as insulation and reduce the ability of the aquastat to sense heat. Have your heating guy check this. Also what type of boiler do you have, some are better than others for hot water. One last thing, a flow restricter can be put in the line to slow the speed of the water going through the coil so it has more time to pick up heat.

Hope this helps,

Leo

John Couture

aquastat?


Hey Leo thanks for all the input!! Unfortunately, that doesnt appear to sound like my problems cause either The boiler is relatively new (less than 5 years) and just had a cleaning last summer. We have city water, so i dont think that enough mineral build up or gunk would accumulate in one years time to affect the system in this way (although i could be wrong). I originally thought that it was a faulty aquastat. After some research, i found out that the aquastat is a high-limit type. That doesnt make much sense to me though! Shouldnt it be a low-limit type to make sure that the water temperature doesnt drop below a certain threshold?? That would ensure that i always have water at a minimum of X degrees.... what do you think? Thanks again!!!

Leo

It should be

The aquastat should be a low limit typt so it will maintain a certain temperature. I get my numbers mixed up but there is an aquastat that can be wired to be either low or high limit. I don't have my book in front of me to know what yours is.

Leo