Joined on January 19, 2012
Last Post on July 22, 2014
@ August 8, 2012 9:26 AM in PolybutyleneThis thread has been an eye opener for me. I really expected with 210 views I would here a few stories of failed poly in low temp closed loop heating. I think I should ask the inspector and consultant to provide some cases to back up their opinions.
I suspected that this was the buyer's "out" earlier. I just wish they had picked a different one.
Thank you all,
@ August 7, 2012 10:01 PM in PolybutyleneLooks like this may be a deal killer. The Buyer has found a "consultant" who has painted a dim view of PB.He claims failure is certain and that the home may be uninsurable.
Does anyone know of resource that has "case studies" or other research on the longevity of PB in this application.
@ August 3, 2012 2:12 PM in PolybutyleneMark,
With all the information (and misinformation) out there, it is always good to get a reality check.
@ August 3, 2012 2:09 PM in DHW Tank TempI set mine just over 140 off and about 125 on. I use a thermostatic mixing valve at the heater to prevent scalding. Many of the newer exchangers are designed to reduce mineral build up. I have good lick with Triangle Tube Smart and Heat-Flo.
@ August 3, 2012 11:24 AM in PolybutyleneGentlemen,
I am working with a client who is trying to sell his home.
The heating system consists of polybutylene tubing. It is grey vanguard circa 1993. 3/4" mains feed 3/8" tubing embedded in gypcrete. The manifolds are also PB (infloor brand block style). The boiler is the second for the house and is a teledyne endurance (formerly heatmaker). The boiler show signs of corrosion and the water is rusty. The system has outdoor reset mixing and runs at a max temp of 130.The tubing shows no sign of discoloration and is pliable.
The buyer had an inspection performed in which the inspector noted the corrosion on the boiler. He also noted the polybutylene tubing and made reference to the class action lawsuits of the 90's.
The buyer is very concerned about the tubing.
I have tried to educate the buyer that the lawsuits were more about the fittings and that his larger problem is the lack of oxygen barrier,poor quality manifolds and failing boiler.
I have recommended the following:
The system should be cleaned
The manifolds should be replaced
The boiler, DHW exchanger and circulators exp tank ect.should be replaced with stainless.
I would probably use TT prestige solo with a heat-flo exchanger.
My question is,
Does anyone have reservations about the polybutylene's longevity in this application?
Has anyone seen failure of polybutylene in this type of system (low temp heating).
Any thoughts on a better solution?
Thank you in advance,
@ August 2, 2012 10:05 PM in Baseboard Heating and Electrical OutletHot water baseboards do not run anywhere near as hot as there electric counterparts.The water inside will never exceed 200 degrees and generally is under 180. They do not present fire hazard and I am unaware of any code issues.
@ August 1, 2012 9:19 PM in Mod-Con Boiler Pump SpeedsYou could add up the pipe sizes and fittings on the secondary then draw out the system curve for the loop. You would then calculate the heat emitted by the radiators on this loop being sure to derate each for the loss in temperature from the previous. This will give you your target GPM. You would then compare this info to the pump curve at the various settings.
My head hurts just thinking about it!
I would use a gauge
@ August 1, 2012 9:02 PM in Indirect HW design questionThe only issue I see with your drawing is that you are not "pumping away" I also think it will be difficult to get an accurate temp to the radiators (especially with outdoor reset)
I agree with the firetube hx comments. Personally I would pipe It as shown in the triangle tube manual posted above. I would run the boiler on outdoor reset and domestic priority. The smart 100 basically has no head loss. It is just a big vat of water. The smart has so much surface area that at a slow circ speed you will likely condense the boiler through much of the DHW cycle
@ August 1, 2012 11:51 AM in What are my options?How much mileage did you get out of this one?
I would suggest a mod/con combi unit. Triangle tube challenger comes to mind. What are you domestic water needs? What part of the country are you in?
Is it possible to replace the vent? ABS may be an issue.
@ August 1, 2012 11:44 AM in Mod-Con Boiler Pump SpeedsI would suggest taking some time to get your head around the "hydronic formula".
Check out this gauge http://www.firedragonent.com/DM6802B.htm .
With the clamps you can quickly see how circulator speeds are effecting your system performance.
It looks like Medium is a decent starting point for the primary (I did not see a minimum flow in the manual).
If you get the secondary speeds to low you may get poor performance on the return side radiators.
I would start with a 20 degree delta t on the heat and see how it goes.
@ August 1, 2012 12:37 AM in Mod-Con Boiler Pump SpeedsI think you may be misunderstanding the speeds on the circulators. I am assuming you have grundfos 15-58s? The gpm produced by the circulators is determined by the point at which the pump curve intersects the system curve (page 27 of the manual) The 15-58 on the boiler set on high will produce about 5.5 gpm (assuming the near boiler piping is short). To figure out the system curve and gpm for the rest of the circulators you would need the pipe lengths and resistance of those components. It would be easier to measure the delta t (supply temp-return temp) of the pipes and adjust the circulators accordingly.
The only way to increase boiler efficiency is to reduce the return water temp. Slowing the boiler circ. will do this (at some point performance will suffer). Slowing the secondary circs may not have an effect on the boiler return temps. Doubling the secondary delta t will have no effect on the primary return temp if you cut the flow rate in half to do it.
Get a gauge and check it out,
@ July 31, 2012 11:51 PM in Hot Water Heater ProblemI absolutely think the issue is with the end switch on the DHW zone valve. You can slide the lever on those valves and tell if the valve is open. An open valve will slide with no resistance. If you valve is open and the boiler is not firing it is an end switch problem. I agree that the wiring is a bit on the ugly side. You may have a loose end switch wire. Next time it fails, try wiggling the groups of red wires. I am 99% sure a new zone valve will solve this. Be sure the contractor has one on his truck.
@ July 31, 2012 11:31 PM in Basbord addition, hydrolic adjustmentNils,
This one is a bit difficult to follow. Could you post a picture of the boiler piping?
Do the downstairs heaters get warm?
@ July 31, 2012 11:22 PM in line voltage and low voltage thermostatsIt sounds like you have 2 questions?
For the indirect do you have a line voltage boiler control circuit and are trying to use a low voltage aquastat? Most boilers have a "T-T" terminal for low voltage control.
What are you trying to do with the fan/can?
What products are you working with?
@ July 29, 2012 10:08 PM in off topic,plumbing ?With no PRV at the meter I would use a gauge that records the high (little red needle) You may be seeing much higher spikes. I assume you have checked for rogue check valves that may be trapping pressure. The other posts are good suggestions as well.
@ July 29, 2012 10:00 PM in Domestic HWH for OWB backupHow often will you use the backup? If the answer is seldom, I would use a conventional atmospheric boiler. Bob's suggestion of an injection mixing pump would be easy for this arrangement.
If you plan on using the backup more often(or just want a sweet setup), I would suggest a mod/con boiler. The piping and controls become a bit more complicated. I recently worked through a design with tekmar using a (2) mod/con boiler controller and a 0-10 vdc circulator on OWB exchanger making this circulator boiler 1 (fixed lead).The Mod/con is boiler 2 (fixed lag)
I think your heat loss assumption is high. Unless you have huge DHW needs, you wont need a boiler anywhere near 199K.
How were you planning on doing the tubing? Most radiant installs will not emit more than about 30K per foot. There is no point in having more boiler than your emitters can radiate. You will be guaranteed short cycling. Siggy has some great stuff on OWB's.
@ July 27, 2012 12:43 PM in Domestic HWH for OWB backupHow did you arrive at 60K . Is it a tent?
How do you plan on keeping the system from air locking? Is the boiler going to be installed on a hill behind the house?
How are you going to mix the infloor water to the appropriate temp?
The house should be pressurized.
You should use a heat exchanger.
The floors should be controlled via outdoor reset.
You should not use hot water heaters for heat(use a boiler)
I understand that the OWB folks are telling you otherwise. I have redone several systems that were originally piped as you are suggesting.
@ July 26, 2012 9:57 AM in OT basement humidier off for two weeksWhy not put an inexpensive condensate pump on your dehumidifier?You would never have to empty it again.
I agree with Ice on the water heater.
@ July 24, 2012 8:20 AM in Heatflo HW tankI like heat flo hot water heaters. Is gas an option? I didn't understand if your question is about boilers or water heaters, or both. Triangle tube does not do oil burners.
@ July 24, 2012 7:39 AM in Hot Water Heater ProblemWhen the motor starts going on those valves, they will no longer trip the end switch inside. If you replace the power head on the zone valve you problem will be solved.
@ July 21, 2012 11:58 PM in repiping old radiant boilerI don't think I would be to concerned about balancing. A pressure gauge on the supply and return would do the trick.This approach would get the job done, but would not be very practical. There are many manifolds with flow gauges available that will show GPM. They are not very expensive and are fun to look at. As SWEI said, the trvs will keep the system in check. Unless your loops are drastically different in length and load,, you should be fine with a simple manifold.Isolation valves are always a good idea.
@ July 21, 2012 11:43 PM in Older Heat Timer Box vs. New Jazzed up EMS BoxCrunch,
It is good to here you have found someone who can advise you.
Best of luck in your journey.
The best troubleshooters I know do not start out knowing the answer, then spending endless hours trying to prove they are correct. They look at the problem from an "open" mindset, the problem and solution then presents itself.