Best Of
Re: Replacement Gas Boiler Size
Ideally it runs for 10 minutes anytime it fires. This allows the firebox and flue to dry opt and the return temperature should be at or above 130°‡
With that size boiler, and low mass fin tube I assume it heats up quickly? On a mild day I would bet it only fires for a few minutes?
If the system has multiple zones, modulating boiler is an ideal fit.
ALL boilers should have periodic maintenance, mod cons can run several years between clean and checks.
hot_rod
Re: Temperature-over-time charts for a well-functioning system?
Yes, with multiple branches you need to balance somehow. The problem with manual valves is they cannot sense temperature change.
The thermal valves notice a temperature drop and open, which allows the delta P circ to ramp up. The entire system should regulate within a few degrees anywhere in any loop.
Idronics issue 24 goes into more detail
hot_rod
Re: Vents for floor drains and similar situations
It may vary from code to code
With a 3” toilet, the vent can be as far as 12’ from the fixture.
2” horizontal up to 40’, or more if you increase the pipe size
hot_rod
Re: Spanish power grid
Three reasons for using DC power links: Reduce losses and line costs on long links (you don't need intermediate substations to compensate for cables), undersea links (cables have high capacitance), and linking systems together that are not synchronous or different frequencies (japan).
How the converter stations operate is another consideration. Most of the converter stations (certainly the older ones) are based on thyristors. These devices can be switched on electronically but rely on reversing current flow to switch off. So they will only work when connected to a working AC system. In many ways they are same as PV and wind turbine inverters that also require a working AC system.
Some of the newer converter stations are based on IGBTs and these can act as a voltage source just like a spinning generator.
The way PV and wind turbines are connected to power grids is becoming a problem with higher levels of penetration and a reducing amount of spinning metal. It does not have to be this way. With modern power electronics "inertia" can be created with the right control strategies.
In some ways the whole renewable strategy seems to be to make connecting thousands of small devices as cheap and simple as possible and let someone else solve the problems this creates.
John
JDHW
Re: Spanish power grid
DC is used for a number of the very high power interconnects — including the ones between France and Spain. Problem is, while they can contribute power if needed, they can't do anything to stabilise grid frequency and thus oscillations. Hence… lights out. The problem is being worked on… but nowhere near to practical engineering never mind installation yet.
Re: 25 Year Review...This Damn House!!
QUOTE from above:
EBEBRATT-Ed Member Posts: 17,710May 4
LOL. My house was the same way. I only fixed everything so i could sell it. Never had the time to fix my own place but had the time to fix everyone else's crap.
My Response:
Similarly, it is said, "a carpenters house is always unfinished" and " the mechanic wife's car is the last to be repaired"
All the Best,
RTW
RTW
Re: Replacement Gas Boiler Size
3 cycles in an hour is not short cycling if the burner is actually firing the whole time there is a call for heat. Get ezzyt to look at it, he is one of the best.
mattmia2
Re: basement heat
Be careful about return ducts in the basement if you have a gas or oil furnace requiring combustion air from that space
