Water Heater Flushing Question

[TromboneAl]

It seems pretty obvious, but before I start this flushing procedure:

I want to get confirmation that I understand the schematic, and have identified the valves correctly:

 

[ERD50]

Actually, to my eyes, the schematic does not seem to match that valve arrangement, but functionally it looks correct and I think your ID matches the intention.

It's just that to me, the schematic shows V3 & V4 as simple on/off, and they look to be diverter valves in the picture, and vice-versa. But it works the same.

Do they supply the pump with the purchase? How often do you need to do the flush?

edit - the more I look at it the more confused I become. I would want to see those valves outside the system so I could understand which way they divert, it is possible they are installed backwards and it would work fine in the regular mode, but flushing would end up connecting you to the supply, not the coils.

-ERD50

 

[Bimmerbill]

I've been meaning to do mine. Maybe this is a good weekend project. I don't have a pump tho. I always thought I'd just hold up the 5 gal jug of vinegar, above the valve, so gravity would do the work.

 

[TromboneAl]

I came to the same conclusions. I called their tech support, but it was very hard to communicate ("there's a valve that looks like a bird or a butterfly, and then..."). I sent them the above illustration and photo, and they replied "Please call our tech support department."

I bought a pump that attaches to my drill for $11,like this:

One is supposed to do the flush every year.

 

[ERD50]

I came to the same conclusions. ...

I think their drawing is wrong, and the install is probably correct.

To test it, I'd:

A) take the cover off the V2 port, attach a hose and then open V2. The V4 valve should be diverted away from V2 as it is now, so you should maybe get a few drops, that's all.

B) Turn the V4 valve, and now V2 should be connected to the tank, so it will drain a bit, but that's all. If you get supply pressure, then that V4 would be wrong, IMO.

C) Return V2 and V4 to original positions.

D) Same process with V1/V3, except when you turn V3, you should get supple pressure (routed through the tank).

If the diverters are going the wrong way, you might be able to change it by removing the handle and swapping it 180 degrees - that might change the orientation inside. I'm guessing it is a ball that turns with a "T" channel in there which should be symmetrical, maybe, I think, well, could be, I dunno.

-ERD50

 

[ratto]

I think Al's understanding on the schematic and valve markings are correct.

It will be very interesting to know what kind of descaling solution and its concentration will be called for. If it's only going to run through the heat exchanger for 45 mins, then the white vinegar probably won't do unless allowed to soak overnight.

 

[F M All]

I think Al is correct.

The diagram can be related to the install:-

Gas line - marked as "gas" - this helps!!

V1&V3 are on the hot line with the curious symbol at the top - physically the hot line has a red washer (clue?) and a pressure release valve on the side with an overflow pipe going through the wall

V2&V4 are on the cold line with a filter - physically the cold line has a blue washer (clue?) and a black plastic item above - I think this the filter that needs to be cleaned after the flush

If the valves 3&4 were not installed correctly would the system work at all? As it has worked it is reasonable to assume they are ok.

Before starting the job the hot vs cold line could also be determined by touch.

 

[JOHNNIE36]

I've been meaning to drain (flush) my water heater for about a year. Great thread but it got me to wondering about the vinegar flush. I had never heard of this and it's got me interested. I know several guys that have done it and no one has ever mentioned the vinegar flush. Would having a softener make a difference in the need to flush the water heater?

 

[bld999]

Are you talking about a tankless as in discussion here? Or a conventional tank type?
Tankless typically need descaling, tank-type just plain water flushing, and eventually anode replacement.

Softening is a benefit with scaling, I believe.

 

[ERD50]

I've been meaning to drain (flush) my water heater for about a year. Great thread but it got me to wondering about the vinegar flush. I had never heard of this and it's got me interested. I know several guys that have done it and no one has ever mentioned the vinegar flush. Would having a softener make a difference in the need to flush the water heater?

T-Al has one of those fancy 'tankless' water heaters. They require an acid flush like this, as they are heating the water instantly, and any build up really hits efficiency. I've never heard of any kind of acid flush with a standard tank type heater.


Another thing seems odd in those instructions. It looks like they have you turn the water on and then remove the filter for cleaning? Unless it has some kind of built in disconnect valve built into that filter, that would seem like a Three Stooges type move. Have Lena take a video.

-ERD50

 

[pb4uski]

Looks right to me. V3 and V4 isolate the water heater fro the rest of the domestic water system. V1 and V2 are diversion valves used of the flush and pump the cleaning solution through the heater the same way the water flows through the heater. Then the solution is flushed out with cold water and you reverse the process to get back to start.

This has been helpful as I need to do mine soon.

 

[Bimmerbill]

Probably run it thru a bit, then stop, letting the vinegar sit for a while. I have to go home and see what fittings the plumber put on mine. Not sure its a garden hose fitting.

 

[TromboneAl]

Well, I finished the procedure, and all went well, and as expected. I did it before reading your test procedure, ERD50.

In progress:



The only minor problem was that the hose endings all leaked, but by having all the junctions over the pail, that was manageable.

Also, there was packing grease in the water pump, which transferred to hose H1. Hopefully, not too much got into the water heater itself. I didn't see any in the inlet filter.

I caught the error concerning the filter, and left valve V4 off. There was a good amount of stuff in that filter (blue green tiny stones), but it could have gone for a few more years without problems.

The vinegar solution got pretty dirty. Next year it will be even easier.

I almost paid to have a plumber do this, not knowing it could be done by the consumer (my manual didn't have that page). So another $100+ saved. Thanks for the help.

 

[JOHNNIE36]

Sorry, I didn't look close enough at the photo except for the noted valves. I see now that it is one of the tankless type. My sister and BIL have one so I'll have to ask them if they ever service it in this manner. Excuse the mixup.

 

[Nords]

Also, there was packing grease in the water pump, which transferred to hose H1. Hopefully, not too much got into the water heater itself. I didn't see any in the inlet filter.
I caught the error concerning the filter, and left valve V4 off. There was a good amount of stuff in that filter (blue green tiny stones), but it could have gone for a few more years without problems.
The vinegar solution got pretty dirty. Next year it will be even easier.

I was going to ask if the heater was even in need of cleaning, but the evidence speaks for itself!

No worries on the grease... it'll move briskly through the heater into the shower nozzle and wash right out when you shampoo your hair.

I've been meaning to drain (flush) my water heater for about a year. Great thread but it got me to wondering about the vinegar flush. I had never heard of this and it's got me interested. I know several guys that have done it and no one has ever mentioned the vinegar flush. Would having a softener make a difference in the need to flush the water heater?

A water softener makes a big difference in our house... we don't get mineral stains on the showers, tubs, or faucets. I suspect it'll keep a tankless heater clean, too. It might be discussed in your owner's manual or on the manufacturer's website.

Are you talking about a tankless as in discussion here? Or a conventional tank type?
Tankless typically need descaling, tank-type just plain water flushing, and eventually anode replacement.
Softening is a benefit with scaling, I believe.

I flush our (solar) water heater every year and never get any scale or minerals out... just steaming-hot clean water. Sometimes I wonder whether I'm risking more leaking/damage to the drain valve by using it than I'm doing good by flushing the heater.

When we replace our heater I'll have to see if I can cut it open for a post-mortem. I'd love to have a fiber-optic camcorder...

 

[ERD50]

Well, I finished the procedure, and all went well, and as expected. ...

The only minor problem was that the hose endings all leaked, but by having all the junctions over the pail, that was manageable.

Glad it worked out. I'm curious about the leaking hoses though. Assuming those are true Garden Hose Threads, the seal is formed by the rubber washer that sits inside the female connector. Did you have the washers in there? If they are normal tapered plumbing fittings, then you need tape or pipe dope, or just deal with the leaks as you did, no real harm from that.

-ERD50

 

[TromboneAl]

Glad it worked out. I'm curious about the leaking hoses though. Assuming those are true Garden Hose Threads, the seal is formed by the rubber washer that sits inside the female connector. Did you have the washers in there? If they are normal tapered plumbing fittings, then you need tape or pipe dope, or just deal with the leaks as you did, no real harm from that.

-ERD50

They leaked around the hose itself. The things you screw down to clamp the hose to the brass piping could not be made tight enough. I'm taking them back tomorrow.

 

[TromboneAl]

It's Broken!

It worked fine all afternoon, and now it doesn't light. No hot water at all. The water runs, but it's cold.

I've rebooted it, and done everything I can do, but nothing.

So I'll call tech support tomorrow, and probably need a licensed service tech.

DIY doesn't always work.

Any ideas?

 

[REWahoo]

Not familiar with tankless heaters, but sounds like it could be a defective thermocouple.

 

[bld999]

If you have a manual with troubleshooting, look up something like "flow switch" and start there. I am not a tech, but I have read some about the new tankless hwt and condensing boilers, and flow switches are often implicated.

 

[ratto]

For a tankless type water heater, there got to be an on-demand mechanism to ignite gas burner for heating water as already pointed out by REWahoo and bld999.

Could this be possibly related to the packing grease you found in hose H1? I know you said you didn't find any grease in the inlet filter. Can you tell the packing grease's viscosity, and do you think it's possible for any grease to pass the inlet filter (based on how fine the filter is and the water pressure)? Also how long it was working fine for "all afternoon", couple of hours continuously? Not sure packing grease, if any left inside, could be the cause, but I would suggest to get a big pail of boiling hot water, and run through the system for at least 10 mins just like what you did with vinegar yesterday to see if it will make any difference before calling for pros. Be sure to let boiling hot water to run through the pump inside out at first.

 

[TromboneAl]

It's Working Again!

Before going to bed last night, I tried it again, and it worked fine. This morning it's still working. My hypothesis is that something was blocking the flow somewhere, and it was intermittent.

I called tech support and talked to a technician who was perhaps the dumbest person I've ever talked with. The conversation went like this:

Me: (described what happened).
Him: Well, the flow to the unit may have been impeded, so that it didn't sense it, and didn't turn on.
Me: OK. I noticed that the flow to the faucet was normal, does that tell me anything?
Him: Again sir, if the flow to the unit was impeded, it wouldn't sense it, and wouldn't 't turn on.
Me: I was just wondering if strong flow at the faucet indicated that the flow was OK at the heater.
Him: Again sir, if the flow to the unit was impeded, it wouldn't sense it, and wouldn't turn on.
Me: OK, thanks, I understand that. Is it possible for flow at the faucet to be strong if it is impeded at the unit?
Him: Again sir, [slower] if the flow to the unit was impeded, it wouldn't sense it, and didn't turn on.
Me: OK, well I'll just keep an eye on it. By the way, the instructions were very good, but there may be an error. They recommend that you restore water flow to the unit and then remove the inlet filter.
Him: Those instructions are meant for a licensed service technician.
Me: Yes, but I just thought I'd pass that on, since it could cause problems.
Him: Again, sir, those instructions are meant for a licensed service technician.

Note that in the past, a technician told me that I could do the flush procedure myself -- didn't need a licensed tech.

I'll have to decide in a year whether to do it again myself.


The grease was the consistency standard grease that you'd get at an auto parts store.

 

[ERD50]

Well, the flow to the unit may have been impeded, so that it didn't sense it, and didn't turn on.

He said it multiple times, that makes it true, no?

I think you are fine with the DIY. One thing that might help in the future - before disconnecting everything, set the valves to run out the hose on the outlet side, then flush several cycles that way. With a large diameter hose that should give max flow, and flush out anything that might have gotten in the flow sensor or anywhere else.

I'd be tempted to back-flush it, but since they don't do that in the instructions I'd hesitate, there might be a back flow preventor or something that could be damaged by back flow?

Are there certain parts that are most likely to fail? You might want to stock up on replacements if they are DIY. I keep a spare thermo-couple for my furnace & water heater, and kept a spare belt for the old furnace (newer ones are direct drive).

-ERD50

 

[TromboneAl]

Are there certain parts that are most likely to fail? You might want to stock up on replacements if they are DIY. I keep a spare thermo-couple for my furnace & water heater, and kept a spare belt for the old furnace (newer ones are direct drive).

-ERD50

I don't think there's anything inside that I could replace myself. This is what it looks like (from the web):

 

[ERD50]

I don't think there's anything inside that I could replace myself. This is what it looks like (from the web): ...

Looks pretty scary.

IIRC, this thing made sense for you due to the cost of propane. I honestly can't see turning in my old standard NG bulk water heater, it's 26 YO and going strong with about zero maintenance (I don't even flush it anymore, afraid the pressure-depressure might cause problems) for one of these tankless units. Far too many points of failure plus the annual flush effort. And failures look expensive. I wouldn't be surprised if one service call wouldn't cost close to an entire new standard water heater (<$400). I doubt I'd ever see a payback, installation would mean running some bigger gas lines to that spot.

-ERD50