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[RockyMountain]

This is what's on each pump:
The left is hot water with a check valve, the center is from the cold solenoid, the right two fittings are for soap/wax. To heat only the soap and not the wax or rinse you'd need a different setup, like separate hot and cold gravity tanks with an Erie valve to switch where it draws from. You can do it with solenoids, but I like the Erie valve because it can't fail to supply the pumps.

It works - I've done it with a Paloma and a $60 tempering valve.

Are either the hot or cold lines fed by a gravity tank, or are they both plumbed directly?

Could city water be plumbed directly to your middle line with a solenoid and the hot line be supplied directly from a heater like a paloma that allows water to pass even if it is not up to the 100 degree mark, thus eliminating the need for a gravity tank or buffer tank?

 

[MEP001]

Are either the hot or cold lines fed by a gravity tank, or are they both plumbed directly?

The hot (left fitting with check valve) is supplied from a gravity-feed tank. The cold is from the cold rinse solenoid. With the check valves, the pressurized cold water from the solenoid just blocks the hot from flowing.

Could city water be plumbed directly to your middle line with a solenoid and the hot line be supplied directly from a heater like a paloma that allows water to pass even if it is not up to the 100 degree mark, thus eliminating the need for a gravity tank or buffer tank?

Not without a different way to deliver the soap and wax to the pump. There are zero-pressure regulators for that which work well, but they're pretty expensive and high maintenance. If you're really worried about the tank running dry, you could add a solenoid to it controlled by a low-level float switch to let it fill with cold water.

 

[mjwalsh]

I guess the question is, whether to heat all water or have cold water rinse year round? OR heat water only in the winter and have cold water in the summer months? It would be nice for more experienced operators chime in and let us know how they do it and why…

I think it is a waste to rinse with heated water. For one thing ... I remember a long time ago on the earliest days of Bill's Forum someone commented he couldn't imagine washing down the walls & bays with heated water. I think MikeV has it right with just letting the tank (insulated) water go to "not as warm" during the lull periods. Most of our equipment rooms are maintained at 70 degrees even up north here it seems ... so the coldest the water could get would be the room temperature. Summertime ... the ER (ambient temp) would be more likely much warmer.

Our car wash is set up with warm water just on the soap hi pressure. We just use a simple Dole valve with a small float tank for each bay. We always tell the customers that cars are not supposed to be washed with hot water according to car manuals that we have read. Within a minute of hi press soap the water warms up because of our extra small float tanks.

In our dog wash we use a 3 way proportioning valve that utilizes analog feedback with PID programming within a PLC to more precisely control the water temperature than just a tempering valve.

kingkoin.com youtube USA deficit sleuth

 

[RockyMountain]

Here is a picture of my current plumbing situation:

The black hose is the gravity fed hot water that supplies both high pressure rinse and high pressure soap. (we don't offer high pressure wax) You can see the solenoid that supplies the soap. Could I simply put a T where the black hose is with a hot feed from the gravity tanks and a check valve on one side like MEP001 suggested. On the other a a cold rinse controlled by a solenoid and fed from city water?

 

[MEP001]

The black hose is the gravity fed hot water that supplies both high pressure rinse and high pressure soap. (we don't offer high pressure wax) You can see the solenoid that supplies the soap. Could I simply put a T where the black hose is with a hot feed from the gravity tanks and a check valve on one side like MEP001 suggested. On the other a a cold rinse controlled by a solenoid and fed from city water?

Yes, but you'll need to put hose clamps on the hose from the unloader to the tee or replace the hose with Push-Lok. You could replace the tee with a cross for a cleaner install. I like unions at the pump to make removing the manifold easier:

 

[2Biz]

I think you would also have to move your soap feed between the check valve and hot water inlet. The soap wouldn't feed in its current location. Correct me if I'm wrong....

The only problem I see with this is if the cv fails, you'll have a flooded ER with your hot water being supplied from a float tank.....

 

[RockyMountain]

I think you would also have to move your soap feed between the check valve and hot water inlet. The soap wouldn't feed in its current location. Correct me if I'm wrong....

The only problem I see with this is if the cv fails, you'll have a flooded ER with your hot water being supplied from a float tank.....

A flooded ER isn't desirable. If the cv fails, the cold water would backflow into the holding tanks. That is a concern.

Regarding the soap- when the rinse solenoid is closed, the city pressure would be shut off and wouldn't have an effect, so the soap should be pulled as it is currently. That make sense?

 

[MEP001]

The tank can overflow if a check valve fails, but 1) it's hardly a flood and 2) it hasn't happened with the check valves I'm using.

You can move the soap feed to use the same check valve as the hot water, add a check valve for the soap line, or flip the soap solenoid around to flow backwards. I've done the last one. The hot water check valve adds a bit of restriction on the line and helps the pump draw soap - if your hot water supply lines are too big you usually have to restrict the hot water with the supply shut-off to make it draw soap anyway. The manifold I showed had a check valve on the soap/wax inlet tee for each bay, but they kept failing so I reversed the solenoid flow and removed the check valves. With the rinse pressure now against the "IN" on the soap/wax solenoid, it won't get back to the tanks. One less thing to go wrong is always good.

 

[2Biz]

Ah, yes...That all makes perfect sense...BTW,Mep, what are the cv's you are using? I haven't seen ones like this before? And what is the cracking pressure? You've never had one fail?

 

[RockyMountain]

So a closed solenoid for the soap will not stop city water pressure from pushing back into the tank, but simply turning the solenoid around will and will also let chemical pass?

 

[MEP001]

Ah, yes...That all makes perfect sense...BTW,Mep, what are the cv's you are using? I haven't seen ones like this before? And what is the cracking pressure? You've never had one fail?

We used to use SMC check valves, but the o-ring comes off too easily, then it wants to stick closed, and of course the o-ring ends up getting into the pump and causing problems, plus the spring sometimes unwinds and hangs the valve open. I ordered one of these from Kleen-Rite and took it apart. The seal is a disc and the spring is 100% captive so they can't come off, and there's nothing for the poppet to hang up on or get stuck in. The cracking pressure is extremely low, not as free-flowing as the SMC but I can blow through it pretty easily.

http://www.kleen-ritecorp.com/p-3259-kleen-rite-12-f-x-f-2-12-l-brass.aspx

So a closed solenoid for the soap will not stop city water pressure from pushing back into the tank, but simply turning the solenoid around will and will also let chemical pass?

Right, a solenoid is basically a check valve with a coil to pull the valve open to allow flow in the "checked" direction. With a small orifice solenoid, the spring pressure is plenty to keep the pump from drawing soap if it's not selected.

 

[Randy]

I don’t understand why you guy’s keep fighting with these gravity fed tanks. The simplest solution is to put a Generant regulator on the water inlet, a DEMA injector and feed the pump with reduced city water pressure, Hot and Cold. They aren’t a big maintenance item, in 32 years I think I’ve replaced 3 or 4 regulators, never touched the injectors. No more Float valves, no more over flowing tanks, no check valves, I’ve never had a washed out Cat 310 pump head. The pumps run quieter because they aren’t working as hard to draw suction.

 

[wash4me]

I put in a 250,000 btu triangle tube prestige solo and also used 2 brazed plate heat exchangers. There's the primary boiler loop, hot water loop and glycol loop. This allowed me to use 1 95% efficient boiler on floor heat and our 6 ss bays. There are solenoid valves that inject the hot water after the gravity tank so there's no wait to fill up the tank with hot water. We also have a 120 gallon pressurized storage tank that was already there. I am happy with my system and believe it will be long lived and efficient but I must say I would think about just throwing 2 tankless at it and replacing them when they go bad if i were to do it again.

 

[2Biz]

I don’t understand why you guy’s keep fighting with these gravity fed tanks. The simplest solution is to put a Generant regulator on the water inlet, a DEMA injector and feed the pump with reduced city water pressure, Hot and Cold. They aren’t a big maintenance item, in 32 years I think I’ve replaced 3 or 4 regulators, never touched the injectors. No more Float valves, no more over flowing tanks, no check valves, I’ve never had a washed out Cat 310 pump head. The pumps run quieter because they aren’t working as hard to draw suction.

Randy,

I think this is a good exercise to identify and document the difference between a gravity feed system and pressure feed system and what is required for both. I think you have the best setup (hands down), but I still don’t know how complex of a changeover it would be if I decided to add HW. I know my current setup will not work, even if I add a new boiler/demand heater to my current HW float tank. I would have to replace some of the old Erie Switching Valves and I don’t even want to go there! So, I’m glad you posted. This gives us something else to consider when/if the changeover is made…Thanks!

 

[RockyMountain]

I visited a couple other car washes to look at how they plumbed their pumps. I found one interesting idea. One wash had cold city water for their rinse cycle and used one regulator for all the 6 bays. They had the regulator and then 6 lines and 6 solenoids after it. It seems to work well for them.

Is this a good idea or is a regulator at each pump a better idea?

 

[MEP001]

They might have had a regulator for the rinse for some peculiar reason like the solenoids couldn't open if the water pressure is over 50 PSI. You'd have to plumb the pump the same way with or without a regulator on the cold water line.

Was it a D&S pump stand?

 

[RockyMountain]

Mechanical reprise

I finally had one mechanical company provide a bid. They offered 2 options. Here are the details:

Option 1: Use the existing 80 gallon holding tank, put in 2 rinnai tankless heaters to supply the 10 gallons per minute. Cost : Over $8500.

Option 2: Put in a closed system boiler that circulates glycol through a heat exchanging tank to heat 80 gallons of water and supply 10 gallons per minute. Cost: Over $12,000.

My opinion: This company did not listen to my needs! Option one is overkill. If the 2 rinnai's will provide the needed gmp, why use a holding tank???

They really wanted to go with option 2 because they supplied a tunnel wash with this system a few years ago and it has worked well for them. Really? They wash 300 cars a day and need heated water in many places. I just need some warm water for 3 self serve bays!

The other 2 mechanical companies said they would get back to me asap and I haven't heard from them in over 10 days...

 

[RockyMountain]

They might have had a regulator for the rinse for some peculiar reason like the solenoids couldn't open if the water pressure is over 50 PSI. You'd have to plumb the pump the same way with or without a regulator on the cold water line.

Was it a D&S pump stand?

I don't know if it was D&S or not. I'm not sure how to tell.

You would have to plumb the same way, but the benefit would be only purchasing and maintaining 1 regulator.

 

[RockyMountain]

Conclusion

I think I may just go with a hot water heater/tank all in one. I like 2Biz's idea and I have come to the conclusion that this option provides a great solution for my needs.

I've looked at the AO Smith. I received poor reviews from the mechanical company who gave me the aforementioned bids (although they wanted us to go with their option). Does anyone have an opinion on commercial water heaters from somewhere like George T Saunders, Home Depot or Menards?

 

[MEP001]

You would have to plumb the same way, but the benefit would be only purchasing and maintaining 1 regulator.

You don't need a regulator for the cold water rinse. As I mentioned, the system you saw probably had one because of some odd issue. D&S used to put a regulator on the cold water line because the solenoids they used had a MOPD of 50 psi and couldn't open if the city pressure was higher. I use Dema 473P solenoids right off the line pressure - they have a 150 psi MOPD..

I think I may just go with a hot water heater/tank all in one.

I still think your best long-term option is to go with a high-efficiency on-demand heater and eliminate both the boiler and tank. What would you save by cutting your gas bill down by 20%?