I have a oil fired boiler. I have 3 full bathrooms on the 2nd floor. I have hot water in one bathroom, the middle bathroom gets warm water at the sinks and no hot water at the shower. The 3rd bath has no hot water at all. There is no mixing valve on my system. And the hot water pressure is pretty low. What is going on?

Hi Sean...

Questions for you, OK? Read on...

Do you have a tankless coil in the oil-fired boiler that makes hot water or a storage tank off the boiler?

How often is each bathroom used?

Do you have a recirculating hot water system in place?

Is water flowing from the pipes with no hot water or is it just cold water coming out of the hot water pipes?

Are there any single lever faucets in any of the bathrooms?

Are the shower valves single lever or multi. Handle units?

Finally, when did this become an issue? Is it new, or did this happen over timPlease answer all questions and we will see what we can copme up with on our end, OK?

Thanks...

Mark

PS: I'm off for the afternoon but will check back in later tonight!

I have a coil in the boiler. No storage tank.

Each bathroom is used everyday.

I think it's a recirculating system. Not sure.

Hot water is flowing through the pipes. They are hot to touch in the basement but the further away from the boiler the cooler they are.

All the shower valves are single lever and the sinks are double lever.

This happens every winter, in the summer it is fine.

I appreciate the help. I have spoken to or have had about 10 Heating and plumber guys and no right answers or solutions.

Hi again...

Water is colder in winter so it takes more to heat it so that is part of the problem right there.

Another problem common with these tankless coils is that they get choked down over time and have difficulty getting water through the system to be heated and the result is less hot water for you. Here, most people would recommend that you have an acid wash done to the coil to clear it of the mineral deposits choking the coil down.. With that being said, however, you said you had no issue like this during the summer so I'm figuring this is not your answer... ;)

You mentioned no mixing valve? Do you mean to tell me that there isn't a mixing valve at the tankless coil output? There darn well should be so I am curious about this. Here, boiler water is usually at 160-190F and then it heats the cold water in the coil to real hot (160-180ish) and then gets mixed with cold water via the mixing valve to a normal 125F maximum to be sent out to the home. How is your tankless coil set up? Please let me know more on this, OK?

Now, I am confused by your description of issues here. If the coil/tankless system was the issue, for example, you should still be getting hot water out of the fixtures. It may take some time, but you should get some hot water. The hot water may not last long, but you should get some. Let me know more on this, too. Are you getting some hot and it doesn't last or are you getting NO hot water at all? If no hot water at all then you have another issue here and it will likely focus around one of single lever shower valves having a bad MIXING VALVE cartridge. Let me know more on this, too.

Finally, watts makes a P-3 valve for tankless coils (see image) that is almost like MAGIC in that it reduces the flow/volume of water to be heated by the tankless coil allowing it to heat water more efficiently WITHOUT REDUCING THE PRESSURE at the faucets/shower valves so that may be a cheap next step to take for your system. Here, the P-3 valve gets cut into the cold water line and soldered into place... that's it. It is a usual first step before we end up installing a storage tank system off the tankless coil. The P-3 valve works well enough for maybe 25% of my customers to be completely satisfied with it and not require installing a storage tank so you may want to look into it.

Let me know what you can on all my questions/concerns above, OK?

Mark