Heating problem - I don't understand HVAC

[urhstry]

My OWB is set at 185.
Water temp in the house at the 30 plate HX is 185.
Circulator pump (always on) is taking about 20 degrees off the HX (165) and circulating the water through my oil burner, which is shut off.
House is difficult to get over 65 degrees.
Baseboard heat is the finned copper pipe, no bleeders (loop system). I have bled the system numerous times using the shut offs.....n oair detected.

What is wrong with my heat?? If the outside temp is around 30-40, the house heats fine....but in this bitter cold weather we are having, it can't seem to catch up.

 

[mga]

when the water is passing thru the house pipes, do they feel hot?

do you have zone valves in the house?

 

[November Wolf]

I am guesing that maybe your 30 plate heat exchanger is too small. I have a 40 plate and heat about 2400 sf.

First thing I would try is to increase your setpoint to 195 and see what happens.

 

[KsWoodsMan]

What temperature was the oilburner designed to operate at ? and what temperature IS it operating at ?

As stated, raising the upper setpoint on the OWB will help some.

Installing a larger pump on the OWB to get more BTU's delivered to the house will help as well.

It dosn't sound like the temp of the water in the oilburner is where it should be. It is displacing the BTU's readily enough , it just isn't getting enough to fully heat yout house. Moving more water through the heat exchanger at a higher temperature may well solve this.

 

[urhstry]

mga - Hot? Not totally... I think they should be hotter.

Wolf - You aren't the first guy to tell me that but there are guys on here with a much larger heating area using a 30 plate. (1750Sq ft). I just moved my setpoint to 195 to see what happens.

KS - ??? I know the setpoints on the furnace is 180 and 165.
The old guage on the unit is showing temps at the 150 range but that can't be trusted. I have thermometers on both sides of the HX.. I lose about 20 degrees when it calls on one zone. I am using a 009 pump and my run from the OWB is only 75 feet.

I am leaning to a too small of a HX. But my question would be that if I were to go to a 50 and that doesn't change anything, what's next?

 

[mga]

once those pipes heat up, you shouldn't be able to leave your hand on them.

 

[Marklambert61]

More info needed

Most likely its your have a pluming or valve issue please send me a complete piping diagram of your system I will be glad to help.


Mark

 

[urhstry]

ok, here is what I found out. When my upstairs and downstairs calls for heat, I get a drop across the heat exchanger of 45 degrees or more...so that is the temp of water going through my house and that is why I am not getting heat. I am only circulating 140-150 degrees of water and my house won't catch up.
Now how do I solve this?

 

[urhstry]

Most likely its your have a pluming or valve issue please send me a complete piping diagram of your system I will be glad to help.

piping diagram... you mean the entire house plumbing? or the OWB plumbing..or both?

 

[KsWoodsMan]

If the oil burner is set to come on at 165 and the water temp is 150 or less than it isn't getting the heat it needs to supply your house properly with heat. ( OK , I missed your update while I was typing )

Moving more water through your exchanger will deliver more BTU's from your OWB, the BTU's needed for your house. I looked up the taco 009 and it is rated at 0-8 GPM compared to 0-20 GPM for a taco 7 and 0-34 GPM for a taco 0011. The pump is the weak link in your chain.

Moving more hot water through your system will give you a smaller temperature differential from inlet temp to outlet temp. This should raise the operating temp of the water in your boiler for more heat in your house.

A larger heat exchanger will give you a wider temp differential. But since there isn't enough BTU's being carried to it you still might not be any warmer in the house after the money is spent.

Go with a higher capacity pump depending on how much lift you need from the OWB to the boiler.

 

[Mike Van]

I'm guessing there's air in your baseboards, happened to me awhile back. A system will run & run, but won't get hot. As someone else said, you shouldn't be able tp touch those pipes.

 

[urhstry]

The water temp coming of the OWB stays close to the set point of 195 and recovers pretty quick after a load. So doesn't that say the pump is doing an ok job or are you still suggesting that I get a 007 or 011?

I have bled these pipes about 50 times, there is not much more I can do for that.

 

[builder1101]

we need some plumbing schematics...just draw up something with arrows for direction, and just circle where the water comes from the stove and returns to the stove.

i think you have some stuff going in series somewhere....espeically if you say the upstairs calls and your temp drops significantly on the other exchanger...

if your going to heat mutliple areas in a house, should have 1 pump move the water to the house and return to the stove.

at the house, T off with valves to run heat to whatever/whereever, then have it return to the 'main' return that'll go back to the owb....

and not sure if your DHW is plumbed to be heated, but fyi, the freshest, hottest water should always hit the DHW sidearm, as it requires heat for thermo-siphon....and keep the elbows to the minimum...mine has 1 t on the bottom, 1 90* on the top, going to a 45*, then to a T also holding the relief valve..

 

[mga]

The water temp coming of the OWB stays close to the set point of 195 and recovers pretty quick after a load. So doesn't that say the pump is doing an ok job or are you still suggesting that I get a 007 or 011?

I have bled these pipes about 50 times, there is not much more I can do for that.

how i bleed mine, when i have to, is turn off the power, then manually open one zone valve. (i have 2) then turn the valve open for the drain. then attach a garden hose to my sump pump crock.


then open the feed valve for full water pressure. (you should also have a valve that will prevent the water from recirculating back into the system.) under full house water pressure, it will move any air and debris from the lines in the house. when i can no longer hear or see bubbles from the garden hose, i'll open the other zone valve, then close the first one and repeat.

after like 5 minutes, there is zero air in the system.

then, i put the feed pressure regulator back into the normal position, wait until the system lowers the pressure to 15 psi, then shut everything down. never had a problem doing it like that and never hear a bubble in the pipes.

 

[RacerX]

Does the system operate normally in very cold weather when using only the oil burner?

 

[KsWoodsMan]

The water temp coming of the OWB stays close to the set point of 195 and recovers pretty quick after a load. So doesn't that say the pump is doing an ok job or are you still suggesting that I get a 007 or 011?

I have bled these pipes about 50 times, there is not much more I can do for that.

That tells me the OWB keeps up with the minimal draw being placed on it very easily. If you want more heat from the OWB to get to the house the pump has to be bigger. 20 GPM of 190° water versus 8 GMP of the same water means you would be delivering 2.5 times the BTU's to heat your house. 34 GPM would mean 4.25 as many available BTU's being moved to your heating system.

Yes, I suggest a bigger pump.

 

[Slick]

I agree about a larger pump...well not larger but more volume, your 009 has a pretty low gpm volume but a good head, the 007, 011 etc have lower head and higher volume. To me the 45 degree drop is the key...that's a huge drop, the water is moving too slowly through that exchanger.

A local friend of mine just had the same issue..he was dropping 20-25 degrees in the house but couldn't get the house warm, went from an 007 to an 011 I think and drop is now only 15ish degrees but the house can get as hot as he wants and the furnace doesn't run as often or as long.

 

[bowtechmadman]

I'll check the size of my pump tomorrow. I'm heating nearly 4,000sq ft w/ a woodmaster 5500 and hold 73 w/ no issue, temp range of 165 to 180. Mother was over one day while wife and I were at work...got home and was hit by a heat wave when I entered the house...Mom had decided it wasn't quite warm enough in the kitchen and had it 87 this was w/ 0 degrees outside.
I'm no expert just a user but would be inclined it's either too small of pump (as stated) or you have an air lock somewhere. I had some air in baseboard in a bedroom and could easily tell since the return was nearly cold in that zone. Feel much difference on your zones as far as temp from the individual feeds versus the returns? Air is obviously going to trap in the highest points...best thing I did was put bleeders in at the baseboards.

 

[Marklambert61]

answer

Most likely its your have a pluming or valve issue please send me a complete piping diagram of your system I will be glad to help.

piping diagram... you mean the entire house plumbing? or the OWB plumbing..or both?

Just your boiler loop....However include all conections in the system...

Mark

 

[urhstry]

Does the system operate normally in very cold weather when using only the oil burner?

yes it does. Used the oil all last year..went through a lot of it for a small house but it worked fine