You should be able to take the gate valve apart by un-bolting the top [stem assembly] from the main body of the valve to clean it out.
I am wondering, by the way you describe your valve, as having, "threaded fittings on the valve housing", with no mention of bolts that secure the top of the valve to the bottom? That it maybe ball valves you have there?
Just a thought, no detriment intended.
Any chance of a photograph of the valves?
"Horton"

Horton,

Thanks. They are conventional knife or gate valves-just my description is a bit awkward.

They are installed horizontally, which may explain something about the gunk in there? Two-inch "flex" pvc comes up from the ground and is attached to the valve. The top of the valve attaches to rigid abs elbow. There is nothing flexible at this time of year.

I thought to loosen the valve cover, wedge it open slightly and try to blow gunk out. But, I fear damaging a gasket or something else. It is questionable if I can separate the two cover pieces enough to do anything else.

This whole suction line assembly, installed in a huge rush just a year ago in the cold by a first-time amateur, needs to be replaced and should have been this past summer.

Since I intend to run all winter I should just leave the valves open and leave them alone as I can do any brief maintenance, like clean leaf basket, by turning pump off briefly?

I'm sure you have disassembled these valves. How do they seat, what's in there? Is it worth trying to repair or should I just order a couple new ones (cheap enough)come spring?

These posts help me find my own answers sometimes along with the advice of fellow ponders. Tendency to over-worry seems to be one of my senior traits.

Any more thoughts or guidance will be much appreciated.

Mike

Hi Mike, thank you for the clarification.
You could take them apart and clean them without any major difficulty I'm sure. You may have to replace a gasket, but that is not a big deal.
But I believe you are on the right track by leaving them alone until the spring and doing whatever to them, when it's not so miserable a time to be doing it.
If you go the way of completely replacing them, it would be beneficial to you, for the future, to install at least one union, on one side of each valve, at the same time.
A union on both sides, of each valve,would be even better.
That way you will be able to break open the unions and remove the valves from service easier.
Just think, you have all winter to plan the operation and it will all go like clockwork next spring;-)
Take care,
"Horton"

Hi Horton, one last question if I may. In terms of vertical or horizontal placement of gate valve, do you think it makes any difference in collection of sediment and debris if they are horizontal?

Tip on unions well taken. Pumps have them, ball valves are type with built in unions. I should have done so for gate valves and check valves.

Indeed, winter nights dreams by the fire hoping my system holds up.

Thanks again - Mike

Mike, I would think that on a vertical run line where the orientation of the actual gate of the valve is horizontally, there would be much more chance of a build up of gunk around the gate. But it should not be all that much more??
Pond gunk is like glue, it can infiltrate all the nooks and cranies of the water circulation system and if left to set up, can cause all sorts of problems.
That is why it is wise to take valves apart and clean them. Especially check valves, if you have any in your piping system.

It is probably worth mentioning again, whilst on the subject of sticky pond gunk. That cleaning out the gunk,applies also and more so, to submersible, magnetic type pumps.
The pump's impeller assemblies should be cleaned out regularly.
Especially, prior to winter storage, in the pond or out of the pond.

Not taking the time to clean out the gunk that has accumulated within the impeller housing and around the impeller assembly [rotor and stator] can prove fatal for a pump the following spring, when it is powered up.
The gunk hardens over the winter, seizing the pump up. This will cause the pump to overheat and burn out, within minutes of being plugged in.
Take care,
"Horton"

Hi Horton,
One more again. I intend to re-do a bit of plumbing in the spring, cleaning, replacing,adding unions. I have 5 ball valves, four are 2" the other is 3" They are so simple I never considered a need to clean them (and they have unions) but your comments make me realize I should.

I have had excessive sediment in the settling pond, the streams and the main pond - a real struggle to control but now under control it seems.

I have two fairly high volume external pumps that have been sucking this stuff through, even with some, but not enough filtration.

Sediment going through the pumps has been a worry on my mind for some time. Mike Il told me not to worry as long as it isn't coarse material, but as you say the gunk does build up.

If I am running a lot of water all winter, I suppose the pumps stay fairly well flushed? Would you say I should pop them open in the spring and check seals and whatever? Or is this different from submerged pump?

Everything is beautiful, like mountain streams, in the snow we just had. Hoping only to deal with emergencies that I hope don't materialize for the next few months.

Anything to add to my shopping and to-do list for April?

Thanks again - Mike

Mike, preventive maintenance never hurts. Taking the impeller cover off, and checking it out, plus giving it a clean off can only do good in my opinion. A clean impeller is easier on the pump motor and the energy used.
I put a electricians fish tape through my pond piping and pull a bottle brush back through, to clean them out every fall.
The amount of gunk that accumulates on the inside wall of the pipes is amazing. Especially on the wall of corrugated hose.
Sooner or later they have got to be cleaned out or the build up will cut down on the flow of water through them, if not plug them up completely.
"Horton"