SF-250 Hot Water Coil

Sounds like you have some rather 'nasty' water!!

I like your description of a pipe thread as a circular leak! I've used teflon tape for years with good sucess. I never did like 'pipe dope' sealant. I use RTV in automotive applicatons with good luck so I'm sure it would work fine in water applications.

What PH is your water?? I'm trying to remember what neutral is? PH 7 ?

Greg L

pH runs from 0 (acidic) to 14 (caustic) with 7 being neutral. The Teflon does work well but I always use Rector Seal also. It is a non-hardening paste that works very well. With high pressure steam (>15#), I would not assemble pipe without it.

Edit: just a useless fact here. Did you know human beings are actually acidic? That's right. Our ph runs 5.4-5.6 pH! Must be the tomatoes?

Hi CS, is 'Rector Seal' a type of sealant or a brand name?? I'll have to look for some the next time I'm out on a plumbing supplies run.

Greg

#5 is what we use, at the top of the page. Most plumbing supply houses will carry this stuff. The nice thing about it is even with steam you can usually take stuff apart and put it back together with no grief. The anerobic stuff seals.... forever.

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If you are using stainless threaded joints you must be more particular about how you prep the pipe or you will have leaks everywhere. From many years of working with stainless you need to use both industrial grade pipe tape and use a thread lubricating sealant. Mcmaster Carr company carries a good brand called Slic tite. http://www.mcmaster.com catalog number is 5477K13. I imagine it is similar to rector seal, although we once tried to use a white teflon sealant from loctite and it failed misserably. Remember to wrap the tape clockwise around the pipe with the threads pointed at you as well. With stainless that last fact is as important as any.

Keep in mind when repairing plumbing that has S/S parts in it, that when you take the S/S pipe out of a steel or iron piece you will almost always pull the threads out with it. Both pieces will be junk in that case. So get those parts prior to trying to make repairs.

Rectroseal #5 is the brand and #5 is their best seller. It looks like mustard

#5 is a softset, supposed to allow 24hrs to dry, but I always slapped it on top of teflon. With SS , it's not the best as it doesn't lubricate. The best dope for SS world be teflon with some Oxy8 paste or grease rubbed on the tape BUT unlikely you will find nor want to pay the premium cost of Oxy8. It is one of few oxygen compatible pipe dopes. I like to use good quality teflon ( more in a moment ) and neversieze ( anti-sieze ) lubricant for SS thread fittings. I've never had a leak using this method.

Good quality teflon is still made in USA. It is twice as thick as the imported stuff and you cannot see thru it. There is a right way and wrong way to wrap teflon. Always wrap with the direction of the threads and pull tight while wrapping and stretch the tape into the threads. Pull tighter yet just before you break the tape to lock it in. Do not cut a 6" piece and try to work it. Leave the tape on the roll and hold it underhand inside out. See below.

Cap is right about the tape, get the thick stuff. The thin import tape will not do the job.

I agree with all the comments about the superior quality of American made Teflon tape. As I said I use high temp RTV silicone sealer carefully applied to both male and female threads. It takes a bit of experience but this is what I'm trying to achieve... I want a ring of cured sealant to act as a internal gasket. I want the water pressure to push on this gasket to make the seal tighter. By applying just the right amount of sealant to the female threads an O-ring like amount will be left inside the tightened male-female tread joint. As the water pressure pushes on the cured silicone it tends to make the seal tighter. Like I said it takes practice to get it right and you have to be careful not to have so much sealant or it may drop off and be flushed through the system.

BTY, the original space shuttle disaster on launch was caused by a failed O-ring. A faulty design in which the pressure on the O-ring weakened the seal rather than improving it. There was no retaining crevice for the seal to be forced into under the building pressure, just two huge flat surfaces clamping an O-ring. Once I realized the principles involved I changed the way I apply pipe thread dope!

Yanche

In reality the threads themselves are what performs the sealing. If you use good quality tape and a good quality lubricating pipe dope/sealant you won't ever develope a leak unless the original threads are not cut to tolerance or are damaged. The rtv will eventually fail like the O ring but if you have a good tight thread seal it will never leak with stainless threads. You have to crank stainless threads in with much more force that with brass or carbon steel ones. Also use to wrenches in a scissor like motion so you don't loosen fittings you have already tightened. The dope we use from Mcmaster is about $8 for a small bottle but will go quite a long way.

One other tidbit on stainless threaded connections:

Once any small burr or imperfection causes a piece of the material to tear off look out! Once gauled there are instances when unthreading the joint will take more force than the pipe or base material can withstand and it will break.

Before you assemble any stainless fittings or threaded fasteners take a good look at both sides of the joint to make sure there are no imperfections that might gouge material from either part.

I have found that good quality teflone tape and gasola pipe sealant works well with stainless steel fittings. We have a lot of stainless heat exchangers and steam piping at work running 75 psi. I have not had any luck with retroseal and teflone. The leaks occur when the pipe cools down when equipment is shut down, then re started later. Hope this may help.
George

Hello List--

I talked about the characteristics of a coil using natural migration of the water without a circulation pump. Even though Harman manual shows it can be done without the pump if your tank is within 10', you may find what I found. The hot water will remain at the top of your domestic hot water tank. Once the water at the top reaches 150-160F range, the migration tends to seize.

I have an 80 gal electric element tank. ( Large tank as a condition to meet PP&L 4 Star rating in order receive lower off peak rates. This also applies to my electrically heated hydronic emergency back up to the heat pumps which by the way hasn't burn a single kilowatt in 2.5 years ).

I discovered after a few weeks of use I could only heat maybe 25 gallons of water. The bottom 2/3rd's would tend to stay cold. To resolve this problem, I fished around on Ebay and found a Grundfos UP15-42F pump. The pump was installed yesterday by all 3 of us. ( me, myself & I as usual! ) After an easy installation & temporary wire job, & 10 mins of water circulation I completely turned the water over in the tank as this pump will circulate 8 gals a minute. The temps held at around 95F thru last night at 2200hrs. I was somewhat concerned, maybe I was pumping too fast, not allowing the water time to heat?

0600hrs this morning the water temps in the tank had raised to 115F. Warm enough for a comfortable shower without temp fluctuation's but still a little cool side. Tonight at 1800hrs, the temps in the tank raised to 145F. This is much better, maybe a little warm! My stove output was on a medium fire pumping out 160F warm air.

So, I'll experiment with this latest upgrade and see if I can improve it some more or simply settle back enjoy the warmth. See images below.

BTW--Making a run for coal to the breaker on Friday. Picking up 2500 lbs. This should take me into the end of March.

Since this topic is still active Cap I would prefer you continue here, perhaps if you want to summarize everthing you have done you could write up a how-to.

RESULTS ARE IN:

Based off of last years residential electric bills 3 months 11/05 thru 2/06 and this years electric bills, 11/06 thru 2/07. I consumed 1,250 less kilowatt hrs of electric using the hot water coil loop. I have a 230 vac, 80 gal tank.