Best Of
Re: CH System Overhaul with Cast Iron to PEX Conversion
I believe Taco makes a ODR mixing valve! You set the ODR from the boiler to operate the high temperature zone and you set the Taco mixing valve ODR for the low temperature zone. Basically you’re resetting the low temperature zone off of the already reset high temperature zone.
Re: CH System Overhaul with Cast Iron to PEX Conversion
A mod con is probably a better boiler for that system, you can run odr on it set for the ci radiators then mix it down for the other loads but the mass of the system is likely something you'd need some protection from low return water temps on a ci boiler. Might want to use a control to do the low temp zones that can do odr too.
Do you really need 170 to the CI ever? It is possible you might but is likely you don't.
mattmia2
Re: Noise complaint: can I lower the pressure on my system?
Just from your boiler size I can be pretty sure that vent would be well undersized. To properly know what you need you would need to get an estimate of the total length of your main and its nominal pipe size(s).
Re: Am I being dense?
What’s on the other side of that creepy looking door? Is that where you hide all the trolls?
No you can’t. Water will take the path of least resistance and run in the pump outlet up to the purge valve. A centrifugal pump is unlike a positive displacement pump. There is a path for the water to travel backwards through the pump. Closing those valves above the purge valves will prevent water from going from the feed that enters the system just under the circulator pumps from going the long way around thru the radiators and purging the loops.
The only thing those valves are good for is for swapping out a bad calculator pump. The flo-check on the supply and that valve on the return will keep the water in the radiators when you drain the boiler to replace anything between the flo-check and the return. Boiler gauge, relief valve, circulator pumps, and the like can all be serviced with the water in the radiators staying put. Not a fan of that design. Looks more like a mistake than an intentional design.
Re: How to increase my delta T
you can operate your boiler at 210° safely. When you start to get above 215° there is the possibility of flashing to steam whenever the pressure in the boiler drops to zero on the gauge. Personally, I would use 200° as a maximum for undersized radiators. But that’s just me.
That way, if the control is off by 10°, then you’re not really getting any higher than 210°. And if there is a temperature overrun once it reaches the high limit, you still have a pretty good cushion because water at 12 PSI will not boil until it above 240°F
Re: Mod Con Boilers Ranking
When i was starting my training, some one asked the instructor what the best furnace was to install. His response i still use to this day. They are all crap, some crap is a little better than others but still crap that breaks. After 15years in the trade, parts availability is key, they all break. Also watch for established companies (looking at you lennox) that "obsolete" parts after so many years. Also, consider external controls better than all in one. Easy to source and change a pump or valve when its not part of the unit. Not so much when "we dont make that part or unit any more". Just my thoughts on 15years of hvacr.
Re: Am I being dense?
Yes the shut off valves and the drains are reversed. The shut off valve should be below the drain. You can't purge the way it is
Re: Lochinvar NKC150N - DHW High Temp Issue
No matter what you have DHW set for, when it sees the flowrate the valve switches position. At that point The hot water from the boiler flows through the DHW heat exchanger, the boiler water is already hot because it was heating your house, too hot to produce the temp DHW you have set. now that heat transfers to the domestic water, overtemping your domestic for a period of time until the water in the boiler cools off enough that it can't keep up with DHW, at that point the boiler begins its ignition process and you probably also get a slug of cold water. You need a mixing with a combi boiler when it is running high tem space heating.
GGross
Re: How to pitch this beast radiator
- Run it for a full cycle with the vent off. Does the rad get warm then? If not, then
- Take the bonnet off the valve and make sure the valve is actually functional. If so then
- Flip the vent upside down on the rad above on that riser (floor above) Run again with the vent off on this rad. If it then gets hot, the problem is balancing the two rads.
