Boilers Vs. Hot Water Heater

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 7:08 pm

I don't know much about boilers. What is different about a boiler compared to a hot water heater ?

Post by **Lightning** » Sat. Mar. 14, 2015 7:23 pm

Funny you ask.. In my mind, not much difference actually.. My Grandmother's apartment had a natural gas hot water heater that had fin tubed base board radiators plumbed to it. The thermostat would kick on a little circulator when it called for heat. Simple easy and efficient, cheap install too compared to a traditional dedicated gas boiler..

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 7:27 pm

When I put my basement in I put Pex in the floor and will heat using my hot water heater. That got me thinking what is the difference..

WNY · Post by **WNY** » Sat. Mar. 14, 2015 7:43 pm

I think they basically do the same thing, heat the water.

I've seen people use basic hot water heaters for small pex installations in the floor, like a small garage. Depends on your BTU requirements and heat loss calculations and how much the hot water tank can keep up with the demand?

Here's a good article.

http://www.radiantec.com/systems-sources/domestic ... eaters.php

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 7:52 pm

Thanks to both of you, I guess boilers boil, if you don't need the water that hot a water heater would work fine..

waldo lemieux · Post by **waldo lemieux** » Sat. Mar. 14, 2015 8:05 pm

Generally speaking , a boiler is the heat for a central heat system and a water heater is used to make domestic hot water and usually has a much lower BTU rating. With the improvement in the thermal efficiency of today's homes some can use a waterheater as a central heating system. or something like that .......

Post by **Lightning** » Sat. Mar. 14, 2015 8:10 pm

Right, my grandma's apartment was tiny..
Only about 600-700 square feet.

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 8:14 pm

I'm heating the basement with the water heater doing double duty, well not yet, when I hook it up I will be asking many questions as to what size heat exchanger and pumps, ect.

So far even in this cold winter the temps have not gone below 58* and most of the time it's been 62* or more and thats with no real heat down there. So I think my 40k BTU water heater should do fine if I want it 70* down there.. guess I'll find out in do time..

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 8:17 pm

This is what I am planing , if anyone see's something wrong with this please let me know...

waldo lemieux · Post by **waldo lemieux** » Sat. Mar. 14, 2015 8:24 pm

Why the exchanger and the bypass for it on the floor loop? Glycol loop? I think Id just use a mixing valve instead of an injection loop.....

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 8:30 pm

waldo lemieux wrote:Why the exchanger and the bypass for it on the floor loop? Glycol loop? I think Id just use a mixing valve instead of an injection loop.....

I'm not sure I understand your question. I thought you needed a heat EX, Plus I want to fill that part of the system with clean water, keep the well water out of it since every now and then it turns hard when the conditioner stops working..

The bypass is to keep the temps in the floor right , 80* or so? This is what I have been told to do...

waldo lemieux · Post by **waldo lemieux** » Sat. Mar. 14, 2015 8:43 pm

sorry Grumpy I didnt understand your diagram. I see now that you want to use your waterheater for a heat source and domestic hot water. That seems to me not be a good idea. I doubt it will do a good job at either.... As far as the bypass goes, to mix water with that you need to do stuff that I don't understand, unless you use a mixing valve. hope that helps

grumpy · Post by **grumpy** » Sat. Mar. 14, 2015 8:52 pm

waldo lemieux wrote:sorry Grumpy I didnt understand your diagram. I see now that you want to use your waterheater for a heat source and domestic hot water. That seems to me not be a good idea. I doubt it will do a good job at either.... As far as the bypass goes, to mix water with that you need to do stuff that I don't understand, unless you use a mixing valve. hope that helps

I am using a mixing valve. I figured I would use 20K BTU's for the basement and the rest would be for DHW. From what I researched this should work. If not I'll do something else. But as it stands now I don't even see the need for heat.. If I want it a few degrees warmer I think this will work, I think.. I'm only heating about 900 SF... part time at that....

Post by **Lightning** » Sat. Mar. 14, 2015 9:08 pm

Grumpy, I don't think you need all that extra stuff in there like expansion tanks or heat exchanger. Just a simple loop thru the tank on a circulator pump..

McGiever · Post by **McGiever** » Sat. Mar. 14, 2015 11:17 pm

Think he wants a closed loop to not ever add much if any new water.
Think it can work, it is just that measuring room air temp with thermostat is not a very good way to do this... slab stat gives more accurate control.

Boilers Vs. Hot Water Heater

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