Quick Question?

[jcappe]

I've noticed that when we use the shower or tub it drops the water temp at the OWB 20 degrees. Does this seem like alot of heat being pulled or not. I know it uses quite abit just curious if that is the norm. Thanks.

 

[Chuck Diesel]

I can see how when you use your tub you would drop 20 degrees because you are using 40 to 60 gal. of H2O.
On a normal given day when we shower that the water temp only drops 5 to 15 degrees. Also it has a lot to do with what the temps are outside and if your furnace or boilier is calling for heat. I noticed with my WM that if we take a really hot shower for a long time we put the unit into a shock mode.
Shock mode I mean that when the water temp is 161 or 162, and you are pulling alot of heat of the unit for your shower, 20 mins. later the water temp could be down 20 degrees. And if you have muiltiple people takeing showers or baths.
Every set up is differant. My 2cents. Chuck D

 

[Butch(OH)]

Yes it is normal for the temp to drop quickly when there is a large domestic hot water demand. How quickly depends on how much water your system holds, (more gallons equals slower drop and slower to rise) and if it is actually heating all the water (plate exchanger) or part of it(side arm) I can have the air handler in the shop calling for heat at the same time as the house heat and the OWB temps don't drop as fast as when the ole woman is in the shower. Think of it like this, if you opened the drain on your OWB to a similar sized stream as a wide open faucet and stuck a garden hose in the top to keep it full the temps would drop fast and nobody would be surprised by that right? It's no different when using a heat exchanger, that wide open tap of hot water is X gallons per minute that has to be heated to X temp.

 

[Butch(OH)]

Not exactly. When using a heat exchanger the heat loss would be limited to the BTU capacity of the heat exchanger.

OK Treeco
I made the ASSumptionthat the exchanger is heating all of his domestic water
and if so there would be no differance, x gallons out the tap in the house is same a x gallons on the gound outside

 

[oneoldbanjo]

Another thing to consider is the current ground/water temperature. I know that it takes a lot of hot water to offset the extremely cold water that comes out of the tap this time of year - and that same extremely cold water is going into the plate exchanger, sidearm or water heater to become hot water. It takes a lot more energy to bring the water up to temperature once the ground becomes cold down a the level of the waterline.

 

[mtfallsmikey]

Correct, my son....any HWH or HX will be rated at x gallons hot water @ x deg. temperature rise/hr. Most gas/hot water heaters use a 90 deg. temp. rise as a baseline.

 

[iowaowb]

I have noticed the same for us the drop in temperature, not as severe but noticeable most mornings. We have the plate heat exchanger and 4-5 showers in morning. Woodmaster 5500. I have seen the bottom drop out in the morning if I dont stock it up before every body else takes there shower.

 

[Blazin]

Same here. Mine dips a little, but the plus side is that the breaker is off on the hot water heater!