Double float valves

[OurTown]

I want to install double float valves on this tank. The idea is to have one 199K tankless water heater for three SS bays but I know it won't keep up if all three are using wax or soap. Having one plumbed with hot water and a second one with cold water set a few inches lower should alleviate any pump starving. Worst case is that the water may be cooler in the bay at busy times. Originally I was going to install a buffer tank on the tankless heater and a circ pump but I want that space. Yes, I understand that two valves will mean twice the chance of failure but it is a risk I'm willing to take. Currently, there is a Bob valve in the center of the 10"-ish wide tank with a dang near 8' diameter float. I'm thinking I would remove that and install two Jobe Topaz compact 3/4" long tail models. I would drill 1 1/8" holes with my carbide hole saw and mount them side by side through the tank wall. Am I overlooking something like usual?

https://www.kleen-ritecorp.com/p-43...opaz-compact-long-tail-float-valve-3-4in.aspx

 

[Waxman]

i have 2 jobe topaz valves plumbed above my warm water tank. mine uses well water for cold, so i had to have an air gap to eliminate cross connection possibilities.

it's a little fiddly to get them adjusted right so the water is nice and warm, but overall the jobe topaz has been very reliable.

 

[OurTown]

i have 2 jobe topaz valves plumbed above my warm water tank. mine uses well water for cold, so i had to have an air gap to eliminate cross connection possibilities.

it's a little fiddly to get them adjusted right so the water is nice and warm, but overall the jobe topaz has been very reliable.

Are those the compact type like the ones at KR I linked?

 

[Waxman]

i think they are the standard size.

 

[OurTown]

i think they are the standard size.

What diameter are the floats? According to Jobe they are about 5" which won't work in our tank. They make smaller floats for those valves but they are only for over tank mounting like your set up.

 

[Waxman]

I think mine are the 5 inch ones

 

[Earl Weiss]

IM O you should "T" hot and cold water valves with a ball valve and check valve on each supply so you have a mixture of hot and cold ffeding the float valve. This will give enough supply and you can adjust the Ball valves depending on outside temperature.

 

[2Biz]

Ourtown,
I basically just did the same thing with my cold water gravity tank....This winter has been rough with a lot of water main breaks and lower water pressures. With the 1" softener I currently have installed, it creates even more head pressure that minimizes flow at lower pressures. What I did was put a 1" Hudson valve with the 1" clamp on adapter on the tank. Its sits quetly in the corner of my tank! I put it about 2" below the normal water line so it will come on fairly quickly if needed. I have it plumbed to a spigot ahead of the softener not affected as much by the softener head pressure issues...You could put in a much smaller, 5-6" float on your BOB valve that should give you enough room? So far so good on my little experiment! Untill the Hudson fails open! LOL....BTW, I did just like you, looking for other varios options...I couldn't find anything that would work in the space I have other than the Hudson. A lot of farmers use them for livestock. I've read the reviews on Amazon and watched YT videos....Not many compalints! Plus I didn't have to cut any holes in my tank!

Amazon.com: Hudson Valve 3 Mounting Bracket f/1" Hudson Water Valve : Industrial & Scientific

 

[OurTown]

IM O you should "T" hot and cold water valves with a ball valve and check valve on each supply so you have a mixture of hot and cold ffeding the float valve. This will give enough supply and you can adjust the Ball valves depending on outside temperature.

I would rather have something that I don't have to mess with on a seasonal basis. Also, I don't think I would ever have hot water except in the summer when the incoming water is warmer.

 

[OurTown]

Ourtown,
I basically just did the same thing with my cold water gravity tank....This winter has been rough with a lot of water main breaks and lower water pressures. With the 1" softener I currently have installed, it creates even more head pressure that minimizes flow at lower pressures. What I did was put a 1" Hudson valve with the 1" clamp on adapter on the tank. Its sits quetly in the corner of my tank! I put it about 2" below the normal water line so it will come on fairly quickly if needed. I have it plumbed to a spigot ahead of the softener not affected as much by the softener head pressure issues...You could put in a much smaller, 5-6" float on your BOB valve that should give you enough room? So far so good on my little experiment! Untill the Hudson fails open! LOL....BTW, I did just like you, looking for other varios options...I couldn't find anything that would work in the space I have other than the Hudson. A lot of farmers use them for livestock. I've read the reviews on Amazon and watched YT videos....Not many compalints! Plus I didn't have to cut any holes in my tank!

Amazon.com: Hudson Valve 3 Mounting Bracket f/1" Hudson Water Valve : Industrial & Scientific

Bob does make much smaller floats but it would still sit in the middle of the tank and may not leave enough room on the side for another float. The tank is not quite 10" wide. Maybe with a smaller float, the arm would need to be much longer so it is possible there would be room for a Jobe. As far as cutting holes in the tank if I put overhead mount type valves then I would be cutting out a large area of the lid if I wanted to still utilize it.

 

[2Biz]

Bob does make much smaller floats but it would still sit in the middle of the tank and may not leave enough room on the side for another float. The tank is not quite 10" wide. Maybe with a smaller float, the arm would need to be much longer so it is possible there would be room for a Jobe. As far as cutting holes in the tank if I put overhead mount type valves then I would be cutting out a large area of the lid if I wanted to still utilize it.

I just slid my lid back. The valve takes up about 4-5" in the corner and you don't have to worry about a float. I'll snap a photo when I go up there today....I'll be able to get rid of this valve when I install my 1.5" softener...Head pressure goes from 20psi for the 1"to about 4 psi with the 1.5"! When pressure drops to 30-35psi incoming, I start seeing issues. At 40-45 everything is ok! This winter, a huge main that fills the tower that I am on ruptured and took them a while to discover the leak...The tower darn near ran out of water,causing the Low Pressure. How do you plan for everything that gets thrown at us!

 

[2Biz]

Here ya go....I see your delima, my issue is hopefully temporary. I keep this area covered with a micro fiber towel to keep any debris out of the tank...

 

[Keno]

Maybe you can use a Madison float switch attached to solenoids if space is an issue. Or use 1 float valve and 1 float switch

 

[Earl Weiss]

I would rather have something that I don't have to mess with on a seasonal basis. Also, I don't think I would ever have hot water except in the summer when the incoming water is warmer.

You can set and forget but you would save money by using less when not needed and more in really cold weather.

 

[OurTown]

I ordered two compact Jobe Topaz long tail valves to try.

 

[Keno]

You can set and forget but you would save money by using less when not needed and more in really cold weather.

There are also auto mixing valves avaliable, if you want to mix and have a set and forget solution

 

[OurTown]

You can set and forget but you would save money by using less when not needed and more in really cold weather.

If I'm looking at this situation correctly then the easiest solution is to just turn down the water heater output temp to where it would keep up but I think it will be too low. Probably somewhere around 75F.

 

[Greg Pack]

So you tankless guys: is there a way plumb a tankless unit that will work as a open loop recirculating boiler? I know some people are using them for floor heat. It seems like most SS tanks would be plenty big and offer enough storage that a single 199K would be able to keep up with many bays. It does decrease efficiency somewhat but would be a much simpler system.

 

[2Biz]

On my 199k Takagi for floor heat, at 105° output temp with inlet temps between 55° and 70°, I get about 6.6gpm flow....The output is directly related to the delta rise between incoming and outgoing...PLUS you have to have enough inlet pressure to get the maximum outlet volumn stated in the manual/advertising. When a manufacturer like takagi boasts 10gpm, you have to have 100 psi inlet pressure to get that advertised output. So all things to consider when going this route! My gravity tanks are quite big, but only hold about 10 gallons of water each...For instance, With 4 bays all running hot HP at about 12-14gpm, how long would the 10 gallon gravity tank last with only 6.6 gallons filling it?! Its a time bomb... It can and will happen...If its winter time and the inlet water is less than 55°, you won't get 6.6 gpm....Output is based on inlet temperature and pressure. A circulating system could possibly eliminate a starved pump situation, but then you have a more complex system...

About the only way I know to use a demand heater safely for SS bays, is to have a 50-80 gallon holding tank that the demand heater keeps at the desired temp using t-stats and circ pump. Cold city water is fed to the holding tank and the circ pump and demand heater keeps the holding tank heated. The holding tank then fills the gravity tanks as normal...If you were to ever run out of heated water, then cooler water is automatically fed to the gravity tanks. But you would never run the risk of starving a pump... JMHO

 

[Greg Pack]

Thanks for the input. My plan would be just to keep the existing cold water valve feeding the tank so there would be no danger of starving the pumps. I would then recirculate the water through the heater and back to the tank. You mention 6.6 gpm flow and that is enough for two bays to run continuously. I think my Coleman tank is at least 10 gallons which provides a nice buffer and would allow three bays to run hot water for several minutes before the water cooled appreciably. I'm guessing that setup would work fine probably 90% of the time. IIRC, when I had a money manager on my Coleman system rinse and foam brush accounted for nearly fifty percent of meter time.