Shaver - DHW with elec WH problems

Arborist Forum

Help Support Arborist Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
well nothing REAL new on this but I did put the overflow mod back on and it seemed to help a bit.

I also timed the pump from kick-on to kick-off. Stove set at 140-145, WH set at 100-105. Now this 100-105 is with the Ranco probe affixed to the outside of the water casing on the WH. Rough calculations are that the internal water temp equivalent is 116-122. It takes 25 minutes to raise the WH temp so that pump kicks off. THis seems way too long.

I've got a Taco 011 pump, 1" pex, ~ 200' total run and a 50gal WH.

Anyone ever time their pump recovery? Any other ideas? Our elec bill is certainly lower which is great, but HW is so inconsistent - it's just frustrating.

I thought about moving the probe to the bottom or center of the WH, but it's really not possible, there's just no room. I also just thought about moving the DHW coil in the stove right above the peak of the firebox.
 
Last edited:
I tried the coil that came with the Shaver four different ways. Out the bottom in the top, out the top in the bottom, out the cold water supply line back in the hot line to the house, out the hot and in the cold. All of those worked to some degree but not good enough for a family of four in the evening. We ran out of nice hot water during or right after the second shower and forget running laundry or the dishwasher at that time. I'm using a 40 gal tank and my furnace temp is 150 to 160. The water never gained heat very fast so it would have to recirc the water for about 30-45 minutes the heat a batch of water. I think the velocity through the coil was too fast for good exchange of heat but I was afraid that if I slowed it down so I had hot water coming back that the volume would be too low to heat the tank fast enough to suit us.
My dad retired his old Taylor furnace and I scavenged the coil out of it and plumbed it so I take water out of the bottom of the heater and return it to the top. Now we don't run out of hot water running showers, laundry, and washing dishes at the same time.
All that to say the you don't have to pay much for the Shaver coil and you get what you pay for. For a low demand situation it works fine but for us it didn't.
 
If your OWB has a DHW coil, why would you not just T from the input side of your water heater and use the OWB to preheat all DHW return the hot water into the input of the water heater. You need 3 valves to make the bypass but no pumps, elect, etc. We do have an elect HWH and it is energized to finish off the temp if it drops or is low. It seams that your OWB is set a little low. Mine is just shy of 180 deg. We have instant hot water and it will run hot all day. I will be honest here . Due to adding 150' of line to the hot water circuit if someone cracks a hot water faucet while you are showering your nipples are getting hard. Due to reduced HW pressure vs cold water pressure.
 
My dad retired his old Taylor furnace and I scavenged the coil out of it and plumbed it so I take water out of the bottom of the heater and return it to the top. Now we don't run out of hot water running showers, laundry, and washing dishes at the same time.

So you basically doubled the length of your coil in the OWB AND you take water from the bottom of the WH and return it to the top, correct?
 
Last edited:
I am not a plumber or even very knowlegeable on the subject, but I do have a similar set-up with no problems. If I understand the OP, there is no heat exchanger of any kind (except the OWB itself). Also, if it is run through a domestic coil which I understand it is, this is a closed (not open) system.

My set-up circulates hot water from the OWB to the top of the HW tank. Because colder water is more dense than warmer water it will settle to the bottom of the tank. This is what is circulated back to the OWB. Why would you want to take the hot water from the top of the tank and heat that at the OWB. Seems to me you are fighting the design of the HW tank. The well water sediment is a valid reason if you have that problem.

As an example, my system is controlled by the thermostat in the HW tank just like as described. But I also have a switch to turn it off if need be. The fire went out in my OWB and the temp dropped a bit below 100º. In this case I turned the HW pump off as it makes no sense to circulate that temperature of water. It took several hours to get the OWB up to temp (160º+). At that point I turned the HW pump on and immediately went to take a shower. The water was very, very cold, but within a minute or so it was as hot as ever. I have a wife and two girls, lots of showers lots of laundry often times all going at the same time. Hot water has never dropped in temperature let alone run out.

Just sharing my experience.

Keith
 
If your OWB has a DHW coil, why would you not just T from the input side of your water heater and use the OWB to preheat all DHW return the hot water into the input of the water heater. You need 3 valves to make the bypass but no pumps, elect, etc. We do have an elect HWH and it is energized to finish off the temp if it drops or is low. It seams that your OWB is set a little low. Mine is just shy of 180 deg. We have instant hot water and it will run hot all day. I will be honest here . Due to adding 150' of line to the hot water circuit if someone cracks a hot water faucet while you are showering your nipples are getting hard. Due to reduced HW pressure vs cold water pressure.

I originally had this, (I think - if I catch what you're saying)...previous setup was as follows:
- Cold into the WH actually went to the coil in the OWB
- then out of the coil and into the cold side of the WH.

It basically preheated the water a bit, but with a 200' total run the water would cool off sitting in the lines when no HW was being used and it didn't do much...still had to leave the WH on... hence this most recent effort.
 
I am not a plumber or even very knowlegeable on the subject, but I do have a similar set-up with no problems. If I understand the OP, there is no heat exchanger of any kind (except the OWB itself). Also, if it is run through a domestic coil which I understand it is, this is a closed (not open) system.

My set-up circulates hot water from the OWB to the top of the HW tank. Because colder water is more dense than warmer water it will settle to the bottom of the tank. This is what is circulated back to the OWB. Why would you want to take the hot water from the top of the tank and heat that at the OWB. Seems to me you are fighting the design of the HW tank. The well water sediment is a valid reason if you have that problem.

As an example, my system is controlled by the thermostat in the HW tank just like as described. But I also have a switch to turn it off if need be. The fire went out in my OWB and the temp dropped a bit below 100º. In this case I turned the HW pump off as it makes no sense to circulate that temperature of water. It took several hours to get the OWB up to temp (160º+). At that point I turned the HW pump on and immediately went to take a shower. The water was very, very cold, but within a minute or so it was as hot as ever. I have a wife and two girls, lots of showers lots of laundry often times all going at the same time. Hot water has never dropped in temperature let alone run out.

Just sharing my experience.

Keith

All experiences are welcomed here man - thank you for the info. Yes it's a closed system. Yes the colder denser water settling to the bottom is why I wanted to move the stat probe to the center or bottom of the WH casing. I am only sensing about 1' down from the top of the WH.

So you're pulling water from the bottom of the WH tank and returning it to the top, if I read this correctly. I had thought about that, but I just pluimbed it the way Shaver recommended it. I'm going to try and find a section view of my WH online to see how the internals are plumbed.
 
HowStuffWorks "How Water Heaters Work"

Also, my OWB is 220' from my house if that matters.

Keith

thanks. I've got the basic idea I was meaning I was going to try and look up my specific model to ensure there wasn't anything funky goin on inside. It's a Rheem and from what I can tell it's your standard set-up, just like the link you provided. Thanks!! I love that site....sometimes they have cool animations.
 
I put my pump on a T from the over flow and circulate back into the bottom drain of the WH. I just took a look at mine to try and find a reason for you problem. Is there anyway the pump is installed upside down? Not sure that would make any diffrence. It is just odd, because I don't have any trouble with mine, shower, dishes, etc.
 
So you basically doubled the length of your coil in the OWB AND you take water from the bottom of the WH and return it to the top, correct?

No, when I changed things around I eliminated the coil that Shaver provided. The tubing used for the one Taylor sells is externally finned so it will be much more effective.
Yes, I do now return the water to the water heater at the top.
 
Just wondering if you had looked into the top plate to see if the coil is all the way in the water. Adding a second coil sounds like a good idea also.
 
Just wondering if you had looked into the top plate to see if the coil is all the way in the water. Adding a second coil sounds like a good idea also.

The coil was 100% submerged. My water level is barely , about 1/4 to 1/8", over the vent line. I have a pvc elbow turned up on the vent line to reduce steaming. I think I just wanted more heat than it could transfer with my boiler water temp at about 160F.
I initially planned to go to a longer coil of 3/4" tubing to increase the stay time in the coil but when I was offered the coil out of the Taylor I jumped on it.
 
I put my pump on a T from the over flow and circulate back into the bottom drain of the WH. I just took a look at mine to try and find a reason for you problem. Is there anyway the pump is installed upside down? Not sure that would make any diffrence. It is just odd, because I don't have any trouble with mine, shower, dishes, etc.

I'm almost positive it's not installed upside down, but I'll look tonight.
 
Just wondering if you had looked into the top plate to see if the coil is all the way in the water. Adding a second coil sounds like a good idea also.

I siliconed the top plate shut and have the roof packed full of insulation - I could check but really don't want to rip all that off just to check. I'm 99% sure it's fully submerged as the water water level is only ~ 1/2" below the cutout for the DHW plate.
 
Last edited:
thought:
- Dip tube extends 3/4 down into WH. I'm pulling water from the top, right next to the HW outlet on the WH. If we're using HW and the pump kicks on it's drawing water upwards, towards the HW outlet and the pump....including the incoming cold water.

- Some of that incoming cold water is most likely siphoning over the HW outlet. Water will flow to the path of least resistance and I hypothesize (yes I said that) :) there's more resistance for the water to go through the pump, thus the cold water exits out the HW outlet.

- If I had the pump draw off the bottom, it would be much closer to the dip tube outlet.

- I did move the stat probe to the bottom of the WH this weekend - no difference.
 
have you tried any kind of volume test at the stove to make sure there are no obstructions>?
 
I think a good amount of your problem is you are trying to run the OWB too cool.You need HOT water out there,148 degrees just isnt cutting it,IMO.Id turn it up 10 degrees and see if it changes anything.You still need to deal with the initial rush of cold water.My OWB need to be 180 degrees to have acceptable performance due to hot water only.It can heat my home at 160,but due to hot water needs,I am running it hotter and using some more wood...but thats the way it goes...
 
I think a good amount of your problem is you are trying to run the OWB too cool.You need HOT water out there,148 degrees just isnt cutting it,IMO.Id turn it up 10 degrees and see if it changes anything.You still need to deal with the initial rush of cold water.My OWB need to be 180 degrees to have acceptable performance due to hot water only.It can heat my home at 160,but due to hot water needs,I am running it hotter and using some more wood...but thats the way it goes...

very true hotter water would help my situation. I suppose this is the easiest solution by far. I kinda hate to but I may have to.
 

Latest posts

Back
Top