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DD

DD

Joined on September 29, 2009

Last Post on March 30, 2013

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Calculating propane for tankless

@ March 30, 2013 10:42 PM in Calculating propane for tankless

I'd like to run a tankless (probably a Takagi TKJr) water heater with propane and a gas range as well. I want to use as small a tank as possible so I can transport the tank easily and refill it myself somewhere away from the house.
How do you calculate for this??
Thanks Folks...

Pressure Relief undersized on European Boilers?

@ January 15, 2013 7:46 PM in Pressure Relief undersized on European Boilers?

I recently trouble shot a LAARS wall hung combi boiler. The pressure relief on the radiant heat side kept leaking through. I replaced the original 30 PSI valve with another...and it happened again. I replaced that one...same problem. The gauge on the boiler seemed to be working just fine, it's an analog gauge. The boiler manual calls out a 30 PSI pressure relief.
Here's the rub....The gauge indicates blow off at 3 bar. That's 43.51 PSI ! Even if I fill the unit to a recommended 1.5, that's 21.75 and if the heat brings it up near 2, that's 29 PSI. So I think that most 30 PSI valves will act like the ones I put in and leak slightly as the pressure approaches 2 bar.
Question: Since the blow off set point on the boiler gauge is a whopping 3 bar...shouldn't I be installing a 50 PSI relief valve? Is this 30 PSI assumption a sloppy conversion error on the part of American distributors?
Sorry my faithful country tis of thee but there are a heck of a lot more salesmen these days than engineers...

got it

@ May 9, 2012 4:27 PM in recirc for potable tank

fantastic. Thanx for the quick response. I'll look in the pex manual.

recirc for potable tank

@ May 9, 2012 11:35 AM in recirc for potable tank

I want to install a recirc pump that will loop through an electric tank (isolated to serve the recirc only).
How do you size for this? In my case I'm sending the heated water through approx 60' of 1" pex until it reduces to 3/4" then 1/2" pex return to the recirc. The only head will be about 6' to the ceiling.

TACO 501

@ November 25, 2011 7:02 PM in 120vac thermostat wire sizing

I put a continuity test on 5 & 6 on the TACO but it did not close the circuit. I'm wondering if the TACO doesn't function without 120vac power in. I can't add the power in because according to the BIASI RIVA manual you can't introduce voltage to the TT on the boiler. I did a voltage test on the boiler TT and read 20VAC. It seems to indicate that the TT line is actually low voltage. So the manual is wrong or there's some sort of spike that happens now and then that they want to guard against? Turns out I'll wait to talk to the distributor on Monday. Thanks for the help on this.

TACO 501

@ November 25, 2011 7:02 PM in 120vac thermostat wire sizing

I put a continuity test on 5 & 6 on the TACO but it did not close the circuit. I'm wondering if the TACO doesn't function without 120vac power in. I can't add the power in because according to the BIASI RIVA manual you can't introduce voltage to the TT on the boiler. I did a voltage test on the boiler TT and read 20VAC. It seems to indicate that the TT line is actually low voltage. So the manual is wrong or there's some sort of spike that happens now and then that they want to guard against? Turns out I'll wait to talk to the distributor on Monday. Thanks for the help on this.

of course!

@ November 25, 2011 12:14 PM in 120vac thermostat wire sizing

I have a TACO relay on board...its a pump relay...that'll work yes?

of course!

@ November 25, 2011 12:12 PM in 120vac thermostat wire sizing

I have a TACO relay on board...its a pump relay...that'll work yes?

120vac thermostat wire sizing

@ November 25, 2011 11:55 AM in 120vac thermostat wire sizing

I have a Biasi Riva boiler..wall hung..propane..non-condensing. It says that 'any external controls and connection lines must be rated 120vac'.
However the thermostat is a dry contact. I want to use the existing thermostat wire 18-24 gauge from the old boiler that I'm replacing.
Why would a dry contact need 120vac compatability? and if so, what size wire should I run from the boiler to the t-stat...?
Help...the folks at both the distributor and manufacturer are away for Black Friday.

Non Condensing wall hung boiler

@ November 7, 2011 4:25 PM in Non Condensing wall hung boiler

any opinions out there on the Biasi Riva non-condensing wall hung boiler?

great leads..

@ October 19, 2011 12:15 PM in wall hung non condensing boiler

Thanks all for the great ideas..as soon as I get a chance to get back in my office I'm on it.
Jack...right...if you're gonna live in a yurt you have to be prepared for the rough and ready DIY experience. Unfortunately this one has a very cheerful 89 year old lady living in it. Luckily its an out building to the main house where her kids live so she can escape to civilization when needed.

wall hung non condensing boiler

@ October 17, 2011 3:28 PM in wall hung non condensing boiler

I'm looking for a good non-condensing wall hung boiler. This will be for a Yurt (in other words a fancy tent with foil wrap for 'insulation'...word to the wise, don't buy one). It currently has five wall hung steel panel radiators on a single loop. So all I need is a small non-condensing boiler to hang in a little out-building taht will heat this little zone.
I didn't design this originally and I curse whoever did but I want to help out my customer.

why the fast, big pressure rise?

@ October 14, 2011 1:51 PM in pressure flux in primary loop

great thanks.

but the mystery to me is that there is a prv and backflow seperating the system from potable and when the system is cold it rests at 20 PSI. Pressure rises, dramatically, 80 PSI at least, when the heater fires.

pressure flux in primary loop

@ October 14, 2011 12:23 PM in pressure flux in primary loop

I'm currently looking at replacing an on demand water heater (takagi) that is being used for a radiant heat only application.

Yes I know....the application itself is a mistake but what's interesting is the malfunction and I'm curious about any ideas about it because it may apply to radiant apps in general

System:  The primary loop is in 3/4" copper and its a very small loop, maybe 10 linear ft or so with a grundfos pump sending water through the on demand at 2.6 GPM. The loop passes through a flat plate heat exchanger. On the other side of the heat exchanger is the secondary loop that has its own circ pump that sends a circuit through five steel wall hung radiators. The 2.6 GPM flow activates the flow switch on the on demand which then heats the water in the primary loop to 165F.

Problem: Whoever installed this did not include an expansion tank on the primary loop. So what happens is when the on demand fires and heats up the water, the pressure rockets from 20 PSI to over 100 PSI...can't say how much since the gauge only goes to 100.

Solution? : if I install an expansion tank on the primary and set it at 30 PSI will that compensate that pressure jump? Doesn't seem to me like it will be enough to keep it around 30 constant and it also means a steady PSI is dependent on the expansion tank not failing...which of course it will do at some point....and if I work on this then I frigging own it....

General Rule: I'll probably replace the on demand with a boiler but would there always be this large of a pressure jump in any primary loop that does not include an expansion tank?

 

schoolin'

@ May 17, 2011 11:00 AM in schoolin'

Hey does anybody recommend a good online solar THERMAL design course...from site analysis to design, including projected solar harvest and finally to install (although I'm more interested in the design portion as I've installed already and that part seems pretty straightforward)
Preferably NOT a manufacturer's course on one particular product line...

Ph testing of solar circuit

@ May 10, 2011 1:02 PM in Ph testing of solar circuit

It's time to go out and maintainance check  the solar installs I did a couple of years ago. Both are closed loop Caleffi systems with Dow glycol.
I need a reliable, easy to carry, cost effective test kit for Ph etc...
Any suggestions?

anti freeze in closed loop

@ November 25, 2010 3:51 PM in anti freeze in closed loop

I'd like to add anti-freeze to my systems...(closed loop, backflow preventer at boiler feed so it won't mix with potable under any circumstances). I'm assuming that you can no problem as long as its the same that I've used in solar systems i.e. food grade glycol... Dow .

What is the preferred ratio of glycol to water?

Any other tips or precautions on this? I know glycol doesn't transfer heat as well.

energy conversions exactly....

@ November 11, 2010 1:27 PM in Electric boilers

You're pretty much summing up my experience. I've installed a couple and serviced a couple of Thermolecs. I like them and there's good support as well.

The elephant in the boiler room is energy use. The folks who want electric boilers do it because they want to get off the fossil fuels. Leaving out the question of what the utility supplying the electric power is using to run their turbines...coal...natural gas...hydro etc,  I want to give them some sort of an answer other than 'electric can cost just as much or more'...
are there software solutions to this energy design issue?

Electric boilers

@ November 11, 2010 10:44 AM in Electric boilers

I'm looking at two different brands of electric boilers....Thermolec and Electro Industries. Any opinions/experience out there about electric boilers?
This will replace an oil burning boiler. No existing buffer tank. Zone valves. One circ pump. thermo mixing valve to temper water at infloor low temp zone. Copper baseboard on the high temp side.
The client wants electric. There is no option for natural gas and he doesn't want propane.
There's plenty of room in his panel for the amp draw. This one will require a 60 and a 30 amp breaker...

3 questions

@ October 29, 2010 11:31 AM in 3 questions

1. Does a primary/secondary loop design protect against short cycling in most cases? 2. Also, how much can you over size a boiler? 10% of the heat load....30? What's the limit?
3. Does a modulating boiler control short cycling completely if the total load falls within the output range of the boiler?

Combi Co Oil vs. Oil Water Heater w/flat plate HX

@ October 25, 2010 6:51 PM in Combi Co Oil vs. Oil Water Heater w/flat plate HX

I'm thinking of replacing a Brad White Oil fired Combi Cor with a Brad White Oil fired water heater with external flat plate heat exchanger for the heating side. I know that they've improved the Brad White combi cor but I'm not trusting that they've been operational in the field yet.
Plus if the water heater fails down the road it will be less expensive to replace...
Does this make sense?

Still thinkin Brad White Oil

@ October 25, 2010 12:32 PM in 30,000Btu heat load oil boiler

LP gas is an option but the HO is resisting it. I've seen the Phoenix in use as well and its impressive.
How bout that Brad White oil Combicor? I've read varying opinions on it but saw one thread that says their qualitiy's improved with improved coil etc
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