how to keep better the boiler warm

[Patrick4002]

Hello, i have a 100l boiler in the boat who is 30 years old,
he get warm but if i put the power on and heat till he is on temp at 2pm the next morning the water is nearly cold

its a hole job to put a new one in so im thinking of isolating the boiler with 22cm roof isolation

but how do i reduse heat losses by the connection water tubes

Best regards, Patrick

 

[Peter B]

Patrick, that is rather a large HWS for a boat, so yes, it would be nice to keep it. However, heating 100L must take some power if using a resistive element type heating.

Running through the heat exchanger off the engine is the best way to heat water, however is only practical when actually using the boat. If you are getting it up to temperature then such a large volume should hold its heat quite well, and should not be cold by the morning. The loss from the actual pipes from the cylinder to the taps is generally minimal, so does not explain it, and not usually are these pipes insulated.

Has this always been an issue, or just a recent issue..? Also, is it connected to the engine via a heat exchanger..?

It does sound like the insulation is defective anyway. What type of insulation does it have now..? Is it inside an outer casing..? If so, unless it is soaked by a leak it should still be doing its job. The fact it is not suggests there is a leak into it. Is there dampness under the cylinder by the morning..? If not, I suppose you could try wrapping the whole cylinder in an insulating blanket, and seeing if that helps. That's if it is accessible enough to do that. Otherwise, as I found with my boat - a new cylinder solves the problem best.

 

[Patrick4002]

Hello Peter, thanks for your message, the problem is a existing one, we had a very expencive elektricity bill, and now i have installed a off-grid system to support our needs, when opt
imizing this i found out that the boiler was taking a lot of heating power. the boiler is isolated with armaflex type and i have room for a good extra isolation.

to get the boiler out is somthing different all piping is in copper tubes neatly bend and not easy to change to a new boiler by myself.

 

[rslifkin]

Insulate the unit itself, but also the first foot or 2 of the lines coming in and out of it. That should help quite a bit.

 

[koliver]

Insulation doesn't prevent heat loss, but rather only delays it.
If you are using the hot water as a winter heat reservoir in the ER, to keep your engines and all other equipment from frost damage, less insulation on the pipes may be desirable. The ER may have enough sound insulation to also provide insulation from heat transfer to the rest of the boat.
If you turn off the power to the water tank and add some other heaters to the ER you may still use the same amount of electricity while laid up in the winter.

 

[Lepke]

I have a 50 gallon water heater. It sits on 2" Styrofoam and is surrounded by 2" foam including the top. All water lines, including the pressure relief tube are insulated. The cold water input line is insulated for 6 feet. It will hold hot water for 2+ days.

 

[tiltrider1]

I am not understanding OP’s situation. It sounds to me like he is heating his boat with a boiler not just his hot water. If I understand this correctly then it makes perfect sense that his water is going cold once he turns the boiler off. Heating a boat via hot water is very expensive maybe 4x more btu’s.

Now if we are talking about just his hot water then there is a more serious problem involved. A hot water heater could not loose this much heat unless circulation was involved.

Maybe Patrick can help me better understand his situation.

 

[Lepke]

Another problem with older hydronic systems is the failure to insulate the supply and return lines. My boiler was installed when diesel was 25¢/gallon and no plumbing insulation. In really cold weather it used 5+gallons in 24 hours. But I did have nice toasty bilge areas. Insulation on the lines saved about 25%, the water reaching the radiators was hotter, and the return line water was warmer.

 

[SteveK]

Hello, i have a 100l boiler in the boat who is 30 years old,
he get warm but if i put the power on and heat till he is on temp at 2pm the next morning the water is nearly cold

its a hole job to put a new one in so im thinking of isolating the boiler with 22cm roof isolation

but how do i reduse heat losses by the connection water tubes

Best regards, Patrick

Sounds like you have a 25 gal US electric tank, 30 year old. You heat the water and then turn off the electric. 30 years ago tanks were not as well insulated as electric was much cheaper.
Lepke has the best solution for you. Add insulation around the tank. I remember a few years back they actually sold hot water tank insulation blankets. Your idea to use 8 inch insulation will most likely keep the water warm for days. What is the R value, about R20?